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Abbreviation (ISO4): Prog Chem      Editor in chief: Jincai ZHAO

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Progress in Chemistry >

2025 , Vol. 37 >Issue 5: 788 - 800

DOI: https://doi.org/10.7536/PC240614

Review

Application of Ionic Liquids in Lithium Metal Batteries

  • Ji Liu 1, 2 ,
  • Yaochun Yao , 1, 2, * ,
  • Shaoze Zhang , 1, 2, * ,
  • Keyu Zhang 1, 2 ,
  • Changjun Peng 3 ,
  • Honglai Liu 3
Expand
  • 1 National Engineering Research Center of Vacuum Metallurgy，School of Metallurgical and Energy Engineering，Kunming University of Science and Technology，Kunming 650031，China
  • 2 Engineering Laboratory for Advanced Battery and Materials of Yunnan Province，School of Metallurgical and Energy Engineering，Kunming University of Science and Technology，Kunming 650031，China
  • 3 Key Laboratory for Advanced Materials and School of Chemistry & Molecular Engineering，School of chemistry and Molecular Engineering，East China University of Science and Technology，Shanghai 200237，China
* （ Yaochun Yao）；
（Shaoze Zhang）

Received date: 2024-06-21

  Revised date: 2024-10-24

  Online published: 2025-04-30

Supported by

National Natural Science Foundation of China(22108111)

National Natural Science Foundation of China(52064031)

National Natural Science Foundation of China(52104302)

Natural Science Foundation of Yunnan Province(202202AB080013)

Natural Science Foundation of Yunnan Province(202101BE070001-020)

Natural Science Foundation of Yunnan Province(202201AT070098)

Natural Science Foundation of Yunnan Province(202201AU070158)

Xingdian Talent Support Project(YNQR-QNRC-2020-081)

China Undergraduate Innovation and Entrepreneurship Training Program(202210674025)

China Undergraduate Innovation and Entrepreneurship Training Program(202410674078)

Yunnan Provincce Undergraduate Innovation and Entrepreneurship Training Program(S202310674135)

Kunming University of Science and Technology Analysis and Testing Funding(2023M20222202134)

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Abstract

Lithium metal batteries（LMBs）have emerged as a focal point for next-generation battery technology research due to their high energy density. However，the commercialization of lithium-metal batteries is hindered by a series of challenges，including lithium dendrite formation，volumetric expansion，and the rupture of the solid electrolyte interphase（SEI）. Ionic liquids（ILs）are emerging as key candidate materials to address these issues due to their unique physical and chemical properties. Despite the significant potential of ionic liquids in lithium-metal batteries，several pressing issues，such as high costs and high viscosity，need to be addressed. Future research should focus on developing new low-cost，high-performance ionic liquids and further understanding their mechanisms in batteries. Additionally，combining advanced characterization techniques and theoretical calculations to explore the dynamic behavior and interfacial phenomena of ionic liquids in lithium metal batteries will help advance their practical applications. This review summarizes the safety issues involved in the research and development of lithium metal batteries，as well as the research progress of ionic liquids in their application as electrolytes and solid electrolytes in lithium metal batteries.

Contents

1 Introduction

2 The existing challenges confronting lithium metal batteries

2.1 Lithium dendrite

2.2 Rupture of SEI

2.3 Lithium anode volume expansion

3 Application of the ionic liquid in electrolytes of lithium metal batteries

3.1 Concept and classification

3.2 Ionic liquids in liquid-state electrolytes

3.3 Ionic liquids in pseudo-solid-state electrolytes

3.4 Ionic liquids in additives

3.5 Ionic liquids in lithium salts

4 Conclusion and outlook

Key words： lithium metal battery; lithium dendrite; electrolyte; solid-electrolyte interface

Cite this article

Ji Liu , Yaochun Yao , Shaoze Zhang , Keyu Zhang , Changjun Peng , Honglai Liu . Application of Ionic Liquids in Lithium Metal Batteries[J]. Progress in Chemistry, 2025 , 37(5) : 788 -800 . DOI: 10.7536/PC240614

1 Introduction

Lithium metal batteries, as high-energy-density energy storage components, have attracted significant attention in recent years in fields such as electric vehicles and aerospace. However, issues such as lithium dendrite growth in lithium metal batteries lead to reduced safety, hindering their commercial application. To address these problems, researchers are dedicated to finding solutions.
The emergence of lithium metal batteries can be traced back to the early 1970s, when they were first invented and commercialized by Stanley Whittingham, a physical chemist at Exxon Corporation in the United States, marking the beginning of lithium metal battery commercialization[1]. After deployment, it was discovered that the lithium metal anode posed some significant safety issues, among which the lithium dendrite problem was the most critical. If left unaddressed, these dendrites could penetrate the separator, ultimately causing a short circuit in the battery. Subsequent incidents involving short circuits and explosions led to the suspension of lithium metal battery development projects.
SONY first replaced the lithium anode with a graphite anode in 1991 and named it the lithium-ion battery, thus initiating the era of commercialization of lithium-ion batteries[2]. After decades of development, due to the low theoretical specific capacity of graphite electrodes in lithium-ion batteries, the development of lithium-ion batteries has approached its theoretical limit, failing to meet market demands for battery endurance and efficiency. Metallic lithium has a much higher theoretical specific capacity (3860 mA·h/g) compared to graphite anode materials; therefore, researchers have once again turned their attention towards developing the next generation of high-performance batteries using lithium metal. Based on the challenges faced by lithium metal batteries, this paper reviews recent advances in the application of ionic liquids as electrolytes in lithium metal batteries.

2 Current Challenges in Lithium Metal Batteries

Metallic lithium exhibits a low redox potential (-3.04 V versus standard hydrogen electrode), which makes it highly reactive with the electrolyte. Most electrolytes are reduced on the surface of the lithium anode, and the resulting insoluble byproducts accumulate on the anode surface, forming an electronically insulating interfacial film that allows only lithium ions to pass through but blocks electrons, known as the solid electrolyte interphase (SEI). Although the lithium anode possesses a large theoretical specific capacity and the most negative potential, issues arising during charging and discharging processes cannot be ignored.

2.1 Lithium Dendrites

The lithium dendrite issue is the primary problem that needs to be addressed in the development of lithium metal batteries. Dendrites are a collective term for irregular lithium deposits, which can be classified into dendritic, whisker-like, and mossy forms according to their one-dimensional morphology[3]. Rapid deposition of lithium ions causes a sharp decrease in anion concentration on the anode surface, generating a space charge region at the interface between the anode and electrolyte, leading to uneven lithium deposition on the electrode surface and thus forming lithium dendrites. Dendrites possess high mechanical strength; their continuous growth extends from the anode, and once they exceed the strength limit of the separator and pierce through it, they may cause a short circuit between the cathode and anode of the battery, resulting in safety accidents.
When lithium dendrites break off, this portion of lithium no longer participates in reactions and is then referred to as "dead lithium." After dendrite fracture, the newly exposed root region continues to react with the electrolyte to form a new SEI film. Consequently, the formation of "dead lithium" reduces the battery's Coulombic efficiency and capacity due to the consumption of electrolyte and lithium.

2.2 SEI film rupture

A well-formed SEI film not only isolates the electrolyte from the lithium anode, preventing further reactions that consume the electrode and electrolyte, but also facilitates the transport of Li+. When evaluating the quality of an SEI film, key parameters such as its strength and toughness are typically considered. If the SEI film lacks sufficient strength or toughness, it may rupture, exposing the lithium anode and leading to renewed reactions with the electrolyte. This cyclic process causes continuous thickening of the SEI film and increases the roughness of the lithium anode surface, thereby promoting the disordered growth of lithium dendrites.

2.3 Volume Expansion of the Lithium Anode

Because lithium has a low density, there is a volume change of 1.87 cm3 when 1 g of lithium is deposited during repeated dissolution/deposition processes[4]. Therefore, continuous charging and discharging will lead to significant volume changes in the lithium metal anode, increasing internal battery pressure, which can ultimately cause the entire battery to rupture and fail.
The above three critical issues of lithium metal batteries are closely interrelated and inseparable (Fig. 1). To address the challenges of lithium metal batteries, researchers need to deeply analyze the electrochemical properties of lithium metal from thermodynamic and kinetic perspectives. Among these, the issue of lithium dendrites is the most significant obstacle on the path to large-scale commercialization of lithium metal batteries. Therefore, scholars have proposed various solutions from different angles to control or even prevent lithium dendrite growth.
图1 锂负极问题的关系

Fig.1 The relationship between lithium cathode problems

3 Application of Ionic Liquids in Electrolytes for Lithium Metal Batteries

To address the aforementioned issues, scholars have proposed solutions such as electrolyte modification[5], solid electrolytes[6], separator modification[7], and artificial SEI films[8]. Electrolyte modification enables the formation of a desirable SEI film and cathode electrolyte interphase (CEI) film in batteries. Therefore, Wan et al.[9] proposed general design guidelines for electrolytes based on their fundamental requirements. These guidelines indicate that an ideal electrolyte should possess the following characteristics: (1) non-flammability; (2) the formed SEI should exhibit weak adhesion to the electrode, along with low applied interphase overpotential (AIOP), high critical interphase overpotential (CIOP), and high mechanical strength; (3) the resulting CEI should also show weak electrode adhesion and high oxidation stability. These guidelines can guide the development of next-generation high-energy batteries.
In addition, it is widely accepted that the SEI should contain abundant inorganic components[10], and practical evidence has shown that SEI films containing LiF exhibit high chemical stability and mechanical strength; thus, LiF has been identified as the most important inorganic constituent of the SEI[11]. To achieve LiF-rich SEI, strategies using ionic liquids to regulate SEI composition have been proposed and are being employed to guide the design of electrolytes for future high-performance lithium metal batteries.
LiF also exists in the CEI interface on the cathode side of the battery, and some researchers believe that a LiF-rich CEI is detrimental to the rate performance of the cathode. This is mainly manifested by the oxidation or induced defluorination of PF6- and FSI- under high potential or high reaction energy, which leads to the formation of LiF and HF simultaneously. The generated HF corrodes the battery interfaces, causing harmful transition metal dissolution at the cathode and damage to the SEI layer, ultimately compromising the electrochemical performance of the battery. This effect is more pronounced in lithium metal batteries because HF reacts more vigorously with the lithium anode, leading to accelerated capacity degradation and reduced battery safety. Additionally, batteries operated under high cutoff voltage and high rate conditions tend to form thick LiF layers, which restrict Li+ migration and increase interfacial polarization[12-14].

3.1 Concepts and Classification

Ionic liquids (ILs), also known as molten salts, refer to a class of organic salt compounds that are composed entirely of ions and have melting points at or below 100 °C. Typically, ionic liquids possess large volumes and poor symmetry[15]. The research on introducing ionic liquids into electrolytes for lithium metal batteries is extensive.
There are many classification methods for ionic liquids. Firstly, they can be classified according to the composition of the cations into imidazole-based, pyridine-based, quaternary ammonium, pyrrole-based, and piperidine-based types[16]. When classified by anions, they can be divided into halogenated salts and non-halogenated salts[17]. Additionally, ionic liquids can also be categorized based on their acidity or basicity as acidic, basic, or neutral. Among them, acidic ionic liquids can be further subdivided into two types: Lewis acids and Brönsted acids[18].
Imidazolium-based ionic liquids possess characteristics such as low viscosity, high conductivity, and a wide electrochemical window. Garcia et al.[19] investigated the physicochemical properties of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMI][TFSA]), including its thermal stability, viscosity, electrical conductivity, and electrochemical window. The results indicated that this ionic liquid exhibits a relatively high ionic conductivity (15 mS/cm at 25 °C) and a wide electrochemical window (4.3 V) at room temperature.
Pyrrholic ionic liquids not only possess advantages such as high chemical stability and low volatility, but also exhibit various properties and functionalities due to the diversity of their molecular structures. For example, they demonstrate antioxidant properties and high conductivity. These characteristics enable lithium metal batteries to achieve more comprehensive performance advantages.
Compared with other types of ionic liquids, piperidine-based ionic liquids also exhibit lower production costs and toxicity· These characteristics facilitate the application of piperidine-based ionic liquids in fields with stringent cost and environmental requirements· Furthermore, the reduced toxicity decreases the potential risks to operators and the environment during the production and usage of these materials, aligning with the trends of modern green chemistry and sustainable development·

3.2 Ionic Liquids in Liquid Electrolytes

In order to obtain a stable and robust SEI, current electrolyte modification strategies involve altering the solvation structure of the electrolyte through various aspects such as solutes, solvents, and additives. Additionally, the application of systems like high concentration electrolytes (HCE) and localized high concentration electrolytes (LHCE) has alleviated issues such as lithium dendrite growth and the fragility of the SEI to some extent.
Lithium metal anodes combined with Ni-rich cathodes (LiNixMnyCozO2, x ≥ 0.6, x + y + z = 1, NCM) exhibit synergistic effects under high operating voltages, making them potential candidates for next-generation high-energy-density batteries[20-21]. However, the high reactivity of Ni-rich cathodes with lithium metal anodes typically results in poor electrode/electrolyte interphases (EEI), parasitic reactions, and lithium dendrite formation, which are further exacerbated by carbonate-based electrolytes. Therefore, Li et al.[22] developed a mid-concentration ionic liquid electrolyte containing pyrrolidinium fluorinated ions, employing fluorinated ionic liquids and dimethyl carbonate (DMC) as co-solvents, together with a dual-salt system comprising LiTFSI and lithium difluoro oxalate (LiDFOB). The results demonstrated that the cations of the fluorinated IL regulate the solvation sheath of Li+ with rich anions, forming a thinner yet more robust SEI film (Figure 2), enabling long-term stable and dendrite-free cycling performance of the battery under high-voltage operation.
图2 （a，b）利用原位光学显微镜观察使用REF和MTDC的Li/Li电池在1 mA·cm-2下的沉积形态；（c，e）MTDC和REF的循环阴极NCM622的SEM图像；（d，f）MTDC和REF的循环阴极NCM811的SEM图像循环阴极；（g，h）NCM622和NCM811的TEM图像；循环100次后，NCM622在CEI层上的（i）O 1s、（j）C 1s、（k）N 1s、（l）F、（m）B 1s的XPS光谱；（n）MTDC和REF电解液中AFM的典型形态；（o）更换电解质后的NCM622/Li电池示意图；（p）更换电解液后的NCM622/Li电池循环性能[22]

Fig.2 （a，b）Deposition morphology of Li/Li batteries using REF and MTDC at 1 mA·cm-2 observed by in-situ optical microscopy.（c，e）SEM images of circulating cathode NCM622 of MTDC and REF.（d，f）SEM images of MTDC and REF cyclic cathodes NCM811 cyclic cathodes.（g，h）NCM622 and NCM811 after 100 cycles of TEM images，XPS spectra of（i）O 1s，（j）C 1s，（k）N 1s，（l）F，（m）B 1s of NCM622 on the CEI layer.（n）Typical morphology of AFM in MTDC and REF electrolyte.（o）Schematic diagram of NCM622/Li battery after electrolyte replacement.（p）Cycle performance of NCM622/Li battery after electrolyte replacement[22]. Copyright 2022，John Wiley and Sons

Traditional liquid electrolytes with 10–20% molar fraction of conventional lithium salts may reduce the performance of lithium metal batteries due to poor Li+ transport capability and high viscosity[23]. Compared with medium-concentration electrolytes, concentrated ionic liquid electrolytes (CILE) possess higher molar fractions of lithium salts, enabling lithium metal batteries to operate at higher charge-discharge rates.
Nevertheless, the high viscosity still limits the transport rate of Li+ in CILE[24]. Introducing low-viscosity co-solvents into the original electrolyte[25] to reduce viscosity, thereby forming locally concentrated ionic liquid electrolytes (LCILE) can address this issue. Compared with CILE, LCILE offers multiple advantages including a wider electrochemical window, lower flammability, higher Li+ migration rate, and better compatibility with lithium metal anodes.
Liu et al.[26] designed a localized high-concentration electrolyte FEdF incorporating LiFSI. The research results indicate that, compared to FE, the Li stripping/plating process in FEdF exhibits higher reversibility (Figure 3). This localized high-concentration electrolyte combines the advantages of low viscosity and low cost associated with low-concentration electrolytes while ensuring efficient ion migration.
图3 使用FE和FEdF两种电解质的锂金属电池的电化学性能；（a）电池循环电压分布；（b）不同电流密度下的库仑效率[26]

Fig.3 Electrochemical performance of lithium metal batteries using FE and FEdF two electrolytes.（a）Cell cycle voltage distribution.（b）Coulomb efficiency at different current densities[26]. Copyright 2022，John Wiley and Sons

Sufficiently strong EEI can enhance the performance of batteries based on Ni-rich cathodes. Liu et al.[27] investigated the effects of 1-ethyl-3-methylimidazolium cation (Emim+) and bis(fluorosulfonyl)imide anion (FSI-) on the composition of EEI, finding that trifluoromethoxybenzene forms a thin and protective SEI on the lithium anode, while a uniform CEI rich in Emim+-derived compounds forms on the cathode. This study improved the solvation environment using co-solvents, highlighting the dilution effect of fluorinated aromatic compounds on the electrolyte. Although co-solvents reduce the cost of ionic liquid-based electrolytes, the solvent cost of [Emim][FSI] remains high.
The commonly used organic carbonate electrolytes are not only highly volatile and flammable, but also exhibit strong hygroscopicity. This characteristic prevents the electrolyte from being exposed to the external environment, even briefly, as LiPF6 would hydrolyze and release toxic HF and PF5 gas[28-29]. Moreover, these acidic gases can corrode the SEI film[30-31], reduce the battery's Coulombic efficiency, and lead to more uncontrollable lithium dendrite growth.
In light of this, Liu et al.[32] designed a water-organic hybrid electrolyte containing N-methyl-N-propyl-piperidinium bis(fluorosulfonyl)imide ([PMpip][FSI]) and a high concentration of LiFSI. This electrolyte can accommodate 1 mol/L of water without compromising the reduction stability of both the lithium nickel manganese cobalt oxide cathode and the lithium anode. Compared with anhydrous electrolytes (Figure 4), this approach not only reduces electrolyte viscosity but also enhances conductivity and Li+ mobility, eliminating the need for strict control during electrolyte formulation, storage, and transportation. However, challenges remain: MD (molecular dynamics) results (Figure 5) show that in a system with 5 mol/L H2O, water molecules tend to form large clusters in the bulk and generate a reactive surface water layer, which compromises EEI stability. In this study, MD simulations and XPS jointly revealed the behavior of water molecules in the electrolyte and their impact on EEI stability. Once the issue of the reactive water layer is resolved, it may become possible to develop specialized batteries suitable for humid or aqueous environments.
图4 不同盐浓度电解质中分别加入1 M、5 M水以及无水电解质的分子数密度[32]

Fig.4 The molecular number density of 1 M，5 M water and anhydrous electrolyte were added to electrolyte with different salt concentration，respectively[32]. Copyright 2021，American Chemical Society

图5 基于MD轨迹的水聚类分析[32]

Fig.5 Water cluster analysis based on MD locus[32]. Copyright 2021，American Chemical Society

Lithium salts are usually added into ionic liquid electrolytes. Due to the same anions existing in both the ionic liquids and lithium salts, strong Coulombic interactions occur between these anions and cations, which increases the electrolyte viscosity and reduces Li+ transport efficiency[33]. Besides adding low-viscosity co-solvents to form localized high-concentration electrolytes to address the issues of high-concentration electrolytes, another strategy is to find ionic liquids with lower viscosity to reduce the viscosity of high-concentration electrolytes. Ether-functionalized ionic liquid cations demonstrate better performance in terms of viscosity and conductivity compared to alkyl cations[34]. Moreover, ether functionalization can also reduce the interactions between anions and cations, forming a more desirable Li+ solvation structure[35].
Therefore, Warrington et al.[36] reported a new organic ionic plastic crystal (OIPC), namely 1-methoxyethyl-1,1,1-trimethylammonium bis(fluorosulfonyl)imide ([N111,1O1][FSI])[37], as well as two ionic liquids: N-methoxyethyl-N-methylpiperidinium bis(fluorosulfonyl)imide ([C1O1mpip][FSI]) and N-methoxyethyl-N-methylmorpholinium bis(fluorosulfonyl)imide ([C1O1mmor][FSI])[38], which were each mixed with LiFSI at a ratio of 1:1 to form electrolytes. Their density, viscosity, and ionic conductivity were measured at 25 to 50 °C (Fig. 6). Although the viscosity of [C1O1mpip][FSI] reached up to 352 mPa·s at 25 °C, its conductivity was 0.88×10-3 S·cm-1, showing better performance compared to alkyl-equivalent systems at 25 °C (50 mol% LiFSI)[39]. In terms of lithium transference number ( t L i + ), [C1O1mpip]0.5[FSI]0.5 exhibited the best performance among the three electrolyte systems (Table 1). Furthermore, among these three electrolyte systems, the (LiFSI)0.5([C1O1mpip][FSI])0.5 system had the lowest glass transition temperature (-74 °C), indicating that this system has a wide operational temperature window.
图6 三种电解质在25~50 ℃的密度、黏度和离子电导率[36]

Fig. 6 Density，viscosity and ionic conductivity of three electrolytes at 25~50 ℃[36]. Copyright 2023，Elsevier

表1 不同电解质的锂转移数[36]

Table 1 Lithium transfer number of different electrolytes[36]. Copyright 2023，Elsevier B.V

Electrolyte containing 50 LiFS mol% Material type t L i +
[C1O1mpip][FSI] IL 0.47 ± 0.02
[N111，1O1][FSI] OIPC 0.37 ± 0.02
[C1O1mmor][FSI] IL 0.33 ± 0.04
[C3mpyr][FSI][40] IL 0.18 ± 0.01（25 ℃）
[C3mpip][FSI][41] IL 0.2（25 ℃）
Although ionic liquids are widely used in LCILE, studies on the role of cations are still limited. Arano et al.[42] investigated the effects of ionic liquid cations on the composition and morphology of the SEI layer, and the results indicated that they also participate in the formation of the SEI film. Combining advanced characterization techniques with theoretical calculations has deepened the understanding of lithium anode degradation mechanisms. Interactions between electrolytes and electrode materials predicted by MD simulations can guide the selection of more suitable electrolyte additives or the design of more stable electrode structures in experiments. At the same time, observations of electrode surface changes using SEM (Scanning electron microscope) verified the accuracy of the simulation results, providing experimental basis for further optimization of battery design.
Therefore, Liu et al.[43] investigated the effects of 1-butyl-1-methylpyridinium ion (Pyr14+) and 1-ethyl-3-methylimidazolium ion (Emim+) on the electrochemical performance of batteries. The study found that although IL cations have little effect on Li+-FSI- coordination, their distinct coordination with FSI- reduces the viscosity of EmiBE, leading to faster transport of Li+ in EmiBE compared to PyrBE. Moreover, during SEI formation, the cleavage of C-N bonds in the cations generates neutral N0, which participates in forming and altering the chemical composition of the SEI. Through XPS analysis, the study revealed that electrolytes containing Emim+ form more N0 and N+ species in the SEI, thereby stabilizing it.

3.3 Quasi-Solid-State Electrolytes with Ionic Liquids

Although adding specific additives to traditional liquid electrolytes can suppress lithium dendrites to some extent, traditional organic carbonate electrolytes are inherently flammable and explosive. Therefore, replacing conventional liquid electrolytes with safer solid electrolytes is an effective solution[44]. They can be divided into two categories: solid polymer electrolytes and inorganic solid electrolytes. Compared with traditional carbonate electrolytes, solid polymer electrolytes exhibit advantages such as high stability, lightweight, high flexibility, and ease of processing and recycling[45]. Inorganic solid electrolytes are known for their high mechanical strength and simple preparation methods[46]. These characteristics help alleviate the issues faced by lithium metal batteries to a certain extent. Thus, lithium metal batteries equipped with solid electrolytes are widely considered one of the ultimate solutions to replace traditional lithium-ion batteries[47].
Although inorganic solid-state electrolytes, especially oxide-based solid-state electrolytes, exhibit excellent stability[48], they still face challenges such as high manufacturing costs[49] and low ionic conductivity[50]. Converting solid-state electrolytes into quasi-solid-state electrolytes can partially address these issues. Quasi-solid-state electrolytes represent an intermediate state between liquid and solid electrolytes, combining the advantages of both types.
Park et al.[51] introduced 1-butyl-1-methylpyridinium bis(trifluoromethanesulfonyl)imide ([Pyr14][TFSI]) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) into oxidative solid electrolyte powder Li1.3Al0.3Ti1.7(PO4)3 (referred to as LATP). They found that after LATP particles were coated with the ionic liquid, the contact performance between the electrolyte and electrode was improved, and the ionic conductivity increased with the increasing weight ratio of the ionic liquid (see Figure 7). This phenomenon is attributed to the reduction of the solid-solid interface resistance of LATP as the proportion of ionic liquid increases[52]. The development of this hybrid electrolyte provides new possibilities for enhancing the performance and safety of lithium metal batteries.
图7 （a）不同比例PHE的Nyquist图；（b）不同组分比例的PHE的适用系数和离子电导率；（c）不同比例PHE的光学图像（LATP： ILE）[51]

Fig.7 （a）Nyquist diagram of PHE with different proportions.（b）Applicable coefficient and ionic conductivity of PHE with different component proportions.（c）Optical image of PHE with different proportions（LATP： ILE）[51]. Copyright 2022，John Wiley and Sons

Garnet solid-state electrolytes also increase the contact resistance of EEI under humid conditions[53-54]. Meanwhile, polyethylene oxide (PEO), as a commonly used matrix material for electrolytes, tends to crystallize at room temperature due to its regular linear structure, hindering Li+ transfer[55-56]. Electrolytes formed by mixing ionic liquids with solid polymers can enhance conductivity[57]. Liu et al.[58] introduced 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([pyr1,4][TFSI]) to modulate the microstructure of PEO, reduce its crystallinity, and improve Li+ mobility. The mixture was then coated onto a garnet electrolyte and assembled into a battery (Figure 8). First, characterization methods such as XRD (X-ray Diffraction) demonstrated that the PEO/IL coating could stabilize Ga-LLZO decomposition and improve the EEI contact condition; secondly, Li/PEO-IL@Ga-LLZO/Li exhibited excellent stability, verifying the effectiveness of lithium metal hybrid solid-state electrolytes.
图8 Li/PEO-IL@Ga-LLZO/LFP电池方案[58]

Fig.8 Li/PEO-IL@Ga-LLZO/LFP battery scheme[58]. Copyright 2022，John Wiley and Sons

In electric vehicles and renewable energy storage systems, batteries may encounter temperature variations ranging from extremely cold to extremely hot, which requires the batteries to maintain good performance under such extreme temperature conditions, avoiding performance degradation or safety hazards caused by temperature fluctuations. In 2021, Tang et al.[59] reported a quasi-solid-state electrolyte capable of operating normally at -30 °C, using p-tert-butylcalix[4]arene (CTH) as the gel network, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) as the solvent, along with cross-linked benzaldehyde-ended polyethylene glycol (PEG-chos). The results demonstrated that lithium metal batteries based on this ionic liquid exhibited stable charge-discharge cycles and provided a wide electrochemical window even at temperatures below -30 °C. This study expanded the application scenarios of lithium metal batteries. Although significant progress was achieved in low-temperature environments, the performance and safety of batteries under high-temperature conditions still require further investigation and optimization.
In previous studies, the intrinsic physicochemical properties of the SEI and the role of SEI-related interfaces in lithium deposition were not well understood. In 2023, Gu et al.[60] clarified the relationship between the space-charge layer (SCL) and the SEI: due to the poor electrochemical performance of the SEI, when the electromigration current of Li+ through the SEI is lower than the required current, harmful diffusion processes of lithium ions begin, forming an SCL on the SEI surface until the SEI breaks down, which is an early sign of lithium dendrite formation. Based on this finding, Gu et al.[61] designed a Py14TFSI-based solid-state electrolyte called Py-Gel. They compared the j-t transients after a single potential step to different overpotentials, as well as voltage distributions of thin-film electrodes under the same current density and plating/stripping lithium capacity, between two structures, SEI-CV and SEI-Pulse, within this electrolyte. The study found that among the two structures covered by Py-Gel, SEI-Pulse performed better in resisting SCL and lithium dendrite formation and in maintaining the surface morphology of the SEI film, indicating that an SEI with good mechanical and electrochemical properties can suppress SCL formation and thus inhibit the early formation of lithium dendrites.
In addition, during the development of quasi-solid electrolytes, it was found that ionic liquids exist in the form of ion aggregates rather than the expected non-associative ions under practical conditions, which reduces their contribution to ionic conductivity[62]. Therefore, a method for confining ionic liquids has been proposed, whereby ionic liquids are dispersed and restricted within polymer networks, frameworks, or fillers. Current studies indicate that this approach can significantly enhance ionic conductivity, influence lithium ion transference numbers, and improve overall battery performance[63]. However, this method has not been thoroughly investigated in the field of quasi-solid electrolytes for lithium metal batteries; for instance, in quantum mechanical systems, an accurate evaluation system for assessing the state of ionic liquids is still lacking. Excessive content of ionic liquids in the matrix or overly large pores may lead to leakage, causing battery corrosion and environmental pollution issues[64].
Polymeric ionic liquids (PILs) are functional polymers containing ionic liquids within each repeating unit. They can be prepared by direct polymerization of ionic liquid monomers, block copolymerization of ionic liquids with other monomers, or by modifying existing polymers using ionic liquids. PILs combine the flexibility and processability of polymers with the wide electrochemical window, non-flammability, and stability of ionic liquids. These materials have found broad applications in fields such as new energy sources, biotechnology, medicine, materials science, and equipment manufacturing.
While polyionic liquids (PILs) possess these advantages, they also face certain challenges. Firstly, the repetitive polar units in the PIL backbone generate numerous crystalline regions, which reduce ambient ionic conductivity. To address this issue, researchers have proposed various strategies such as copolymerizing multiple monomers and blending different polymers. Liu et al.[65] focused on modifying IL monomers; the synthesized [GIM][TFSI] possesses long flexible side chains that increase the free volume of IL units, thereby enhancing the transport efficiency of Li+ across the repeating units. In this study, LiTFSI and N-methyl-N-methoxyethylpyridinium bis(trifluoromethylsulfonyl)imide salt ([MEMP][TFSI]) were introduced as plasticizers and incorporated into the polyionic liquid P[GIM][TFSI]. The solvation sheath of Li+ is rich in TFSI-, and MEMP+ adsorbed on the anode surface generates an electrostatic shielding effect, collectively promoting the formation of a uniform and stable SEI. This design also avoids the explosion risks associated with conventional organic plasticizers.
Secondly, ensuring good compatibility among the polymer, lithium salt, ionic liquid, and poly(ionic liquid) within the polyionic liquid electrolyte system is a challenge[66]. A semi-interpenetrating polymer network (Semi-interpenetrating polymer network, S-IPN) is a system composed of one or more polymers (networks), characterized by at least one network being penetrated by linear macromolecules, with physical entanglement between cross-linked polymer and linear polymer chains, resulting in synergistic effects that exceed the sum of their individual effects (e.g., mechanical properties). This technique improves the material utilization of conductive polymers without requiring complex synthesis methods or compromising the mechanical stability and mechanical properties of the polymer[67]. Introducing ionic liquid monomers into a polyethylene oxide matrix to form polyionic liquid-based solids with a semi-interpenetrating polymer network structure can also enhance the conductivity and interfacial compatibility of the electrolyte[68].
Gel polymer electrolytes still face challenges such as the difficulty in balancing mechanical strength and ionic conductivity, excessive usage of ionic liquids, and high costs, which limit their large-scale application. In recent years, reports have demonstrated the practicality and effectiveness of single-network polymer electrolytes, semi-interpenetrating network polymer electrolytes, or composite polymer electrolytes (Composite polymer electrolyte, CPE) based on these networks and polymer electrolytes in lithium metal batteries[69]. Therefore, constructing a uniform and stable hybrid network to accommodate ionic liquids, achieving a good balance between the electrochemical performance and mechanical strength of CPE, would contribute to producing both safe and efficient lithium metal batteries. Double-network (Double-network, DN) polymers, as cross-linked polymers containing two independent yet interpenetrating polymer networks, can offer more flexible molecular design and exhibit superior mechanical properties such as strength and toughness compared to single-network polymers[70]. These electrolyte designs not only enhance battery performance but also improve safety and stability, providing new research directions for the development of lithium metal batteries.
As mentioned above, PEO tends to crystallize at room temperature. Some studies have found that imidazolium-based poly(ionic liquids) exhibit strong ion-dipole interactions with the ethylene oxide units along the PEO chains, which can alleviate the crystallization issue[71]. This demonstrates that the incorporation of poly(ionic liquids) can significantly improve the electrochemical performance of PEO-based electrolytes. In the future, different poly(ionic liquids) could be introduced into PEO electrolytes to meet various performance requirements.
Innovation in electrolyte membranes is also a solution to address the challenges faced by lithium metal batteries. A PEO-based organic-inorganic composite electrolyte membrane was prepared by modifying graphene oxide nanoparticles with poly(ionic liquids) containing ethylene oxide groups; the electrostatic interaction between imidazolium cations and TFSI- facilitates the dissociation of LiTFSI in the electrolyte[72]. Additionally, polymer electrolytes based on an S-IPN structure[66] enable significant improvements in both mechanical and electrochemical performance of lithium metal batteries. This novel electrolyte membrane is not limited to specific electrolytes but can be combined with other types of electrolytes to achieve optimal battery performance. This multifunctional electrolyte membrane significantly enhances both the mechanical and electrochemical properties of lithium metal batteries, demonstrating the potential of poly(ionic liquids) in next-generation high-energy-density battery technologies.

3.4 Ionic Liquids in Additives

Electrolyte additives, known as the "vitamins" of batteries, can directly influence the charging and discharging performance of batteries. Li et al.[73] proposed three ideal strategies for addressing the issue of uncontrolled growth of lithium dendrites through electrolyte additives: optimizing the SEI, modifying Li+ solvation, and regulating lithium deposition. Based on the functions of electrolyte additives, they can be categorized into three types: SEI-forming additives, deposition-regulating additives, and auxiliary additives[74]. By carefully selecting and combining these additives, the safety, cycling stability, and energy density of batteries can be significantly enhanced.

3.4.1 Film-Forming Additives

Film-forming additives are a class of additives used to optimize the SEI film, and they are typically consumed during the formation of the SEI. Feng Jianwen et al.[75] believed that an ideal film-forming additive should decompose preferentially over other components of the electrolyte when generating the SEI, and the resulting SEI should meet specific requirements regarding integrity, strength, and stability. Film-forming additives are divided into inorganic and organic types; typical inorganic film-forming additives include lithium nitrate[76], lithium halides[77], etc., while organic film-forming additives include perfluoropolyether (PFPE)[78], tris(hexafluoroisopropyl) phosphate (THFP)[79], among others. Generally speaking, the inorganic components in the SEI determine its mechanical strength and ionic conductivity, while organic film-forming additives can generate polymer byproducts insoluble in the electrolyte during the reaction process. These byproducts possess better flexibility, thereby enhancing the stability, toughness, and elasticity of the SEI.
Imidazolium-based ionic liquids exhibit characteristics of low viscosity and high electrical conductivity; however, they are prone to reduction when the potential is lower than 1.0 V (versus Li+/Li), increasing the consumption of lithium and the electrolyte. Nevertheless, this property enables their preferential decomposition and facilitates the formation of the SEI layer. Additionally, nitrogen-containing cations may enhance the inorganic content, making them suitable as film-forming additives for the SEI layer. Wang et al.[80] introduced Im1(8)PF6 as an additive into conventional electrolytes and analyzed the SEI composition and lithium deposition morphology. The study revealed that lithium deposited using the unmodified electrolyte exhibited whisker-like or spike-shaped structures with larger surface area and more voids, whereas the lithium deposited with the additive displayed a compact and dense morphology, ensuring high reversibility of active lithium and reducing the likelihood of internal short circuits and SEI rupture.
Lithium metal is considered superior, and combining it with layered lithium-rich oxide (LLO) can further enhance the energy density of batteries. However, there are currently two key issues hindering the development of Li-LLO batteries. The first issue is lithium dendrites; the second issue arises during cycling at high voltages, where high-valent transition metal ions and reactive oxygen species are generated. These substances react with the electrolyte on the LLO cathode surface, accelerating the dissolution of transition metals and consequently damaging multiple structures, leading to cathode structural collapse, which results in rapid battery capacity degradation. Therefore, addressing these problems is critical for achieving commercialization of Li-LLO batteries.
To address this issue, Huang et al.[81] proposed the use of a multifunctional ionic liquid additive, 1-ethoxymethyl-3-vinylimidazole bis(trifluoromethylsulfonyl)imide [Vmim102][TFSI]. According to density functional theory (DFT) calculations, this additive can preferentially form protective interfacial films on both anode and cathode surfaces. The vinyl group of this ionic liquid exhibits high electrode affinity, enabling preferential adsorption on the lithium anode and promoting the formation of SEI. Based on DFT calculations combined with characterization techniques such as SEM and XPS, this study guided and verified the effectiveness of electrolyte additives in stabilizing the electrode/electrolyte interface, improving contact with the lithium anode, and reducing interfacial resistance.

3.4.2 Sediment Control Additives

Sedimentation control additives do not participate in film formation within the electrolyte, but they can influence the formation of lithium dendrites. Their mechanism of action involves regulating the deposition behavior of lithium ions to suppress the growth of lithium dendrites[73]. By precisely controlling the chemical structure and concentration of the additives, the characteristics of the SEI layer can be modulated, thereby optimizing the battery's charge-discharge performance and cycle life.
Self-healing electrostatic shield (SHES)[82] can fundamentally alter the morphology of lithium dendrites, promoting a "self-healing" process of lithium instead of the commonly observed "self-amplification" phenomenon in the initial stages of lithium dendrite formation during lithium deposition. When ionic liquids are added to the electrolyte, cations tend to accumulate near the dendrite tips, forming a layer of positive charge that induces electrostatic shielding (Fig. 9). This positively charged ion layer repels incoming Li+ ions from the tip regions, thereby causing Li+ ions to preferentially deposit near the dendrite tips[83]. This mechanism relies on the effective reduction potential of Li+ being higher than that of the cations from the electrolyte additive. The introduction of this mechanism has changed previous understandings of lithium dendrite growth and effectively suppressed the rapid growth of dendrite tips, enabling relatively uniform and smooth deposition of lithium ions.
图9 锂沉积时静电屏蔽示意图

Fig.9 Schematic diagram of electrostatic shielding during lithium deposition

Based on this, designing an electrolyte system with electrostatic shielding effects can effectively regulate lithium deposition behavior. Zhang et al.[84] introduced 1-methyl-1-propylpiperidinium bis(fluorosulfonyl)imide ([Pp13][FSI]) as an additive into the electrolyte. Results indicated that this additive exhibits electrostatic shielding and lithiophobic effects, which facilitate the formation of a stable SEI. Meanwhile, the low concentration and inherent properties of [Pp13][FSI] in this system overcome issues such as high viscosity and poor wettability. From a mechanistic perspective, lithium deposition-regulating additives are not consumed, ensuring their long-term effectiveness. Additionally, only a small amount of additive is required, reducing costs. Therefore, this approach has become a viable solution to address the high cost of ILs.

3.4.3 Auxiliary Additives

The auxiliary additives work synergistically with other additives to enhance the effectiveness of the main additives. Similar to lithium deposition-regulating additives, auxiliary additives do not participate in film formation, but they can influence the overall performance of the battery. These additives improve the electrochemical environment of the battery or enhance the physical properties of the electrolyte, thereby increasing the charging and discharging efficiency, cycling stability, and safety of the battery.
To address the challenges faced by lithium metal batteries, hybrid materials combining organic and inorganic components have emerged as a feasible approach to enhance the mechanical strength and toughness of quasi-solid electrolytes, such as polymer-solid electrolytes and ionic liquid-solid electrolytes[85].
As mentioned above, commonly used polymer electrolyte matrices such as PEO tend to crystallize. Incorporating liquid plasticizers into the original system to form quasi-solid polymer electrolytes can facilitate lithium salt dissociation and reduce the resistance of the EEI. When selecting a plasticizer, in addition to considering its ionic conductivity, attention should also be given to its impact on the overall system safety. ILs, when added as plasticizers into solid polymers, are released under certain pressure and can fill the solid–solid interface between electrode and electrolyte, transforming it into a solid–liquid–solid interface with broader contact area and lower resistance[86], thereby acting as a binder[87]. This strategy can significantly enhance the performance of electrolytes. Moreover, due to the small amount of ionic liquid plasticizer required compared to using ionic liquids as solvents, it helps reduce battery manufacturing costs, making this approach a promising research direction for addressing issues in lithium metal batteries.
Quasi-solid electrolytes enhance their flexibility and processability, allowing for more versatile design of battery shapes in the future, while enabling the fabrication of high-performance lithium metal batteries through a simple and low-cost cold-pressing process. In addition, using different ionic liquids can alleviate the lithium dendrite issue to varying degrees and form a smooth and stable SEI film.

3.5 Ionic Liquids in Lithium Salts

Conductive lithium salts, similar to solvents and additives, are essential components of the electrolyte, and their anions also participate in the formation of the SEI film. However, unlike other components, conductive lithium salts also supply lithium ions for the entire electrolyte system. In traditional electrolytes, the cations and anions of lithium salts usually dissociate after being solvated in organic solvents, and only undergo desolvation when electrochemical reactions occur within the battery. When ionic liquids are used as solvents, the lithium salt ions dissociate due to the electrostatic interactions of the ionic liquid, and their transport process is accomplished through alternating pairing between ions.
Traditional ionic liquid lithium salts, such as LiPF6 and LiBF4, suffer from poor thermal stability and easy hydrolysis; therefore, it is urgent to find suitable alternatives. Imide-based ionic liquids can also serve as conductive lithium salts, among which LiTFSI and lithium bis(fluorosulfonyl)imide (LiFSI) are the most common. These two ionic liquids exhibit high ionic conductivity and excellent chemical stability toward lithium polysulfides and superoxides[88]. When using electrolyte solutions containing LiTFSI, the cycling performance is better than that of LiFSI-based electrolytes, which is influenced by multiple factors, including the electrochemical stability of TFSI- being superior to FSI-, and the reduction decomposition products of TFSI- being more complex than those of FSI-[89-90]. Due precisely to the more complex decomposition products of TFSI-, it is difficult to form a smooth, uniform, and stable SEI film during the first charge, thereby affecting the growth behavior of lithium dendrites. During the charging and discharging processes of lithium metal batteries, the reduction products of TFSI- and FSI- participate in the formation of the SEI layer[91], highlighting the importance of selecting appropriate lithium salts to form a stable and reliable SEI layer.
Although FSI- and TFSI- are widely applied, the study of aging behavior in ionic liquid-based electrolytes has long been insufficient. The components of SEI films containing FSI- and TFSI- were initially investigated, revealing that SEI mainly consists of reduction products of TFSI- and FSI-[92]. Preibisch et al.[93] studied the influence of LiTFSI concentration on the thermal aging behavior of [Pyr14][TFSI] when in contact with lithium and copper. Results showed that the sample without added LiTFSI exhibited the highest degree of aging. At lower salt concentrations, decomposition products of Pyr14+ increased, which was attributed to excess TFSI- forming different but more effective SEI layers on the anode surface, preventing further cationic decomposition. Introducing a small amount of LiTFSI effectively mitigated the aging phenomenon of [Pyr14][TFSI] when in contact with the lithium anode. However, there is still limited detailed understanding regarding the presence and formation process of degradation layers on copper surfaces. Therefore, future studies need to employ advanced characterization techniques to thoroughly investigate these phenomena, aiming to better optimize electrolyte formulations and improve battery cycle life and safety.
Ionic liquid lithium salts provide an effective approach to improving battery performance in lithium metal batteries, especially in enhancing safety and cycling stability. Although ionic liquids offer numerous advantages as salts, the current research has focused on a limited variety of ionic liquids, and other ionic liquid lithium salts with superior properties may be developed in the future.

4 Conclusion and Prospect

There are three major issues in lithium metal batteries: lithium dendrite growth, SEI film rupture, and volume expansion, which severely affect the stability and safety of the batteries and hinder their commercialization. Due to increased research efforts on lithium metal batteries, significant progress has been made in addressing these challenges. Theoretically, the development of theoretical models and prevention criteria for lithium dendrite formation has deepened the understanding of lithium dendrites. Practically, researchers have proposed various solutions, such as electrolyte modification, solid-state electrolytes, and separator modification, to address these issues. Among these approaches, the application of ionic liquids offers unique advantages.
We summarized the application strategies of ionic liquids in lithium metal batteries based on their roles as different components in electrolytes. Among these strategies, incorporating ionic liquids into quasi-solid-state electrolytes has attracted significant research interest.
The application of (poly)ionic liquids in quasi-solid-state electrolytes combines the advantages of non-flammability, wide electrochemical window of (poly)ionic liquids, and the high flexibility of quasi-solid-state electrolytes, making them one of the ultimate solutions for addressing issues in lithium metal batteries. Due to the superior designability of PILs in terms of functional groups and degree of polymerization compared to conventional ILs, the multifunctionality of polymeric ionic liquids should be further explored in the future, such as designing ionic liquids with self-healing capabilities to enable automatic repair of the SEI. In addition, enhancing mechanical strength and improving electrochemical performance will expand their applications in extreme environments and other scenarios.
At present, the application of ionic liquids (ILs) in conductive lithium salts is limited. The commonly used lithium salts, such as LiPF6, LiFSI, and LiTFSI, apart from providing Li+, can also lead to fluoride release through their anions, generating HF which corrodes both the solid electrolyte interphase (SEI) and the cathode electrolyte interphase (CEI). Therefore, future efforts should focus on developing electrolytes that are resistant to fluoride release or utilizing additives to suppress HF generation, thereby minimizing the corrosion of SEI and CEI.
In addition, (poly)ionic liquids face challenges such as high synthesis costs, poor compatibility with other components, and the presence of trace halogen ions during their synthesis, which can easily corrode electrodes, limiting their future large-scale production. Therefore, future research should focus on developing new synthesis methods for ionic liquids, such as using renewable raw materials. At the same time, it is important to explore the interactions between ILs and other battery components to optimize the overall performance of batteries. Through these efforts, current challenges can be overcome, promoting the application of ionic liquids in lithium metal batteries and ultimately achieving their commercialization in broader applications.

References

Publishing order | Descend order by publishing year | Descend order by cited within
[1]
Whittingham M S. Chem. Rev., 2004, 104(10): 4271.

[2]
Huang Y Y. Physics, 2007, 36(8): 643.

(黄彦瑜. 物理, 2007, 36(8): 643.).

[3]
Meng J W, Lei M, Lai C Z, Wu Q P, Liu Y Y, Li C L. Angew. Chem. Int. Ed., 2021, 60(43): 23256.

[4]
Zhang Q. Doctoral Dissertation of Shanghai Jiao Tong University, 2022.

(张强. 上海交通大学博士论文, 2022.).

[5]
Zhou B X, Stoševski I, Bonakdarpour A, Wilkinson D P. Adv. Funct. Mater., 2024, 34(7): 2311212.

[6]
Sun Y, Li J C, Xu S, Zhou H S, Guo S H. Adv. Mater., 2024, 36(14): 2311687.

[7]
Yang D, You D, Bingnan Deng, Wang Q, Ai W X, Zhicong Ni, Zeng Y J, Li X, Zhang Y Y. Ionics, 2023, 29(12): 5161.

[8]
Kim Y, Stepien D, Moon H, Schönherr K, Schumm B, Kuenzel M, Althues H, Bresser D, Passerini S. ACS Appl. Mater. Interfaces, 2023, 15(17): 20987.

[9]
Wan H L, Xu J J, Wang C S. Nat. Rev. Chem., 2024, 8(1): 30.

[10]
Zhao Q, Stalin S, Archer L A. Joule, 2021, 5(5): 1119.

[11]
Jagger B, Pasta M. Joule, 2023, 7(10): 2228.

[12]
Qin K Q, Holguin K, Mohammadiroudbari M, Huang J H, Kim E Y S, Hall R, Luo C. Adv. Funct. Mater., 2021, 31(15): 2009694.

[13]
Ding L Y, Chen Y M, Sheng Y L, Yue X Y, Liang Z. Angew. Chem. Int. Ed., 2024, 63(51): e202411933.

[14]
Bai P X, Ji X, Zhang J X, Zhang W R, Hou S, Su H, Li M J, Deng T, Cao L S, Liu S F, He X Z, Xu Y H, Wang C S. Angew. Chem. Int. Ed., 2022, 61(26): e202202731.

[15]
Shamsi S A, Danielson N D. J. Sep. Sci., 2007, 30(11): 1729.

[16]
Wasserscheid P, Waffenschmidt H. J. Mol. Catal. A Chem., 2000, 164(1/2): 61.

[17]
Jiang W Y, Yu W Z. Met. Mater. Metall. Eng., 2008, 36(4): 51.

(蒋伟燕, 余文轴. 金属材料与冶金工程, 2008, 36(4): 51.).

[18]
Amarasekara A S. Chem. Rev., 2016, 116(10): 6133.

[19]
Garcia B, Lavallée S, Perron G, Michot C, Armand M. Electrochim. Acta, 2004, 49(26): 4583.

[20]
Alvarado J, Schroeder M A, Pollard T P, Wang X F, Lee J Z, Zhang M H, Wynn T, Ding M, Borodin O, Meng Y S, Xu K. Energy Environ. Sci., 2019, 12(2): 780.

[21]
Zou Y G, Cao Z, Zhang J L, Wahyudi W, Wu Y Q, Liu G, Li Q, Cheng H R, Zhang D Y, Park G T, Cavallo L, Anthopoulos T D, Wang L M, Sun Y K, Ming J. Adv. Mater., 2021, 33(43): 2102964.

[22]
Li Y X, Ding F W, Shao Y Y, Wang H Y, Guo X L, Liu C, Sui X L, Sun G, Zhou J, Wang Z B. Angew. Chem. Int. Ed., 2024, 63(8): e202317148.

[23]
Liu X, Mariani A, Adenusi H, Passerini S. Angew. Chem. Int. Ed., 2023, 62(17): e202219318.

[24]
Wu F L, Kim G T, Diemant T, Kuenzel M, Schür A R, Gao X P, Qin B S, Alwast D, Jusys Z, Behm R J, Geiger D, Kaiser U, Passerini S. Adv. Energy Mater., 2020, 10(34): 2001830.

[25]
Meisner Q J, Rojas T, Glossmann T, Hintennach A, Liu Q, Cao J Y, Redfern P C, Ngo A T, Curtiss L A, Zhang Z C. J. Electrochem. Soc., 2020, 167(7): 070528.

[26]
Liu X, Mariani A, Diemant T, Di Pietro M E, Dong X, Kuenzel M, Mele A, Passerini S. Adv. Energy Mater., 2022, 12(25): 2200862.

[27]
Liu X, Mariani A, Diemant T, Di Pietro M E, Dong X, Mele A, Passerini S. Adv. Mater., 2024, 36(1): 2309062.

[28]
Campion C L, Li W T, Lucht B L. J. Electrochem. Soc., 2005, 152(12): A2327.

[29]
Yang H, Zhuang G V, Ross P N. J. Power Sources, 2006, 161(1): 573.

[30]
Kim J, Lee J G, Kim H S, Lee T J, Park H, Ryu J H, Oh S M. J. Electrochem. Soc., 2017, 164(12): A2418.

[31]
Zhou P, Xia Y C, Wu Y H, Hou W H, Lu Y, Yan S S, Zhou H Y, Zhang W L, Liu K. ACS Appl. Mater. Interfaces, 2022, 14(34): 38921.

[32]
Liu Q, Jiang W, Yang Z Z, Zhang Z C. ACS Appl. Mater. Interfaces, 2021, 13(48): 58229.

[33]
Philippi F, Rauber D, Eliasen K L, Bouscharain N, Niss K, Kay C W M, Welton T. Chem. Sci., 2022, 13(9): 2735.

[34]
Rauber D, Hofmann A, Philippi F, Kay C W M, Zinkevich T, Hanemann T, Hempelmann R. Appl. Sci., 2021, 11(12): 5679.

[35]
Shimizu M, Yamaguchi K, Usui H, Ieuji N, Yamashita T, Komura T, Domi Y, Nokami T, Itoh T, Sakaguchi H. J. Electrochem. Soc., 2020, 167(7): 070516.

[36]
Warrington A, Hasanpoor M, Balkis A, Howlett P C, Hutt O E, Forsyth M, Pringle J M. Energy Storage Mater., 2023, 63: 102984.

[37]
Warrington A, Kang C S M, Forsyth C, Doherty C M, Acharya D, O’dell L A, Sirigiri N, Boyle J W, Hutt O E, Forsyth M, Pringle J M. Mater. Chem. Front., 2022, 6(11): 1437.

[38]
Warrington A, O’Dell L A, Hutt O E, Forsyth M, Pringle J M. Energy Adv., 2023, 2(4): 530.

[39]
Liu Q, Dzwiniel T L, Pupek K Z, Zhang Z C. J. Electrochem. Soc., 2019, 166(16): A3959.

[40]
Yoon H, Howlett P C, Best A S, Forsyth M, MacFarlane D R. J. Electrochem. Soc., 2013, 160(10): A1629.

[41]
Liu C Y, Ma X D, Xu F, Zheng L P, Zhang H, Feng W F, Huang X J, Armand M, Nie J, Chen H L, Zhou Z B. Electrochim. Acta, 2014, 149: 370.

[42]
Arano K, Begic S, Chen F F, Rakov D, Mazouzi D, Gautier N, Kerr R, Lestriez B, Le Bideau J, Howlett P C, Guyomard D, Forsyth M, Dupre N. ACS Appl. Mater. Interfaces, 2021, 13(24): 28281.

[43]
Liu X, Mariani A, Zarrabeitia M, Di Pietro M E, Dong X, Elia G A, Mele A, Passerini S. Energy Storage Mater., 2022, 44: 370.

[44]
Varzi A, Raccichini R, Passerini S, Scrosati B. J. Mater. Chem. A, 2016, 4(44): 17251.

[45]
Armand M. Solid State Ion., 1994, 69(3/4): 309.

[46]
Luo C W, Yi M, Cao Z J, Hui W, Wang Y A. ACS Appl. Electron. Mater., 2024, 6(2): 641.

[47]
Chen M H, Yue Z Y, Wu Y X, Wang Y, Li Y, Chen Z. Sustain. Mater. Technol., 2023, 36: e00587.

[48]
Park K H, Bai Q, Kim D H, Oh D Y, Zhu Y Z, Mo Y F, Jung Y S. Adv. Energy Mater., 2018, 8(18): 1800035.

[49]
Chen R J, Qu W J, Guo X, Li L, Wu F. Mater. Horiz., 2016, 3(6): 487.

[50]
Lim Y J, Kim H W, Lee S S, Kim H J, Kim J K, Jung Y G, Kim Y. ChemPlusChem, 2015, 80(7): 1100.

[51]
Park J, Jin H, Yeon S, Kim H W, Ko M. Energy Technol., 2023, 11(2): 2201153.

[52]
Jung Y S, Oh D Y, Nam Y J, Park K H. Isr. J. Chem., 2015, 55(5): 472.

[53]
Yu S, Schmidt R D, Garcia-Mendez R, Herbert E, Dudney N J, Wolfenstine J B, Sakamoto J, Siegel D J. Chem. Mater., 2016, 28(1): 197.

[54]
Han X G, Gong Y H, Fu K, He X F, Hitz G T, Dai J Q, Pearse A, Liu B Y, Wang H, Rubloff G, Mo Y F, Thangadurai V, Wachsman E D, Hu L B. Nat. Mater., 2017, 16(5): 572.

[55]
Wu Y X, Li Y, Wang Y, Liu Q, Chen Q G, Chen M H. J. Energy Chem., 2022, 64: 62.

[56]
Jeon H, Kim D. J. Membr. Sci., 2021, 624: 119029.

[57]
Widstrom M D, Ludwig K B, Matthews J E, Jarry A, Erdi M, Cresce A V, Rubloff G, Kofinas P. Electrochim. Acta, 2020, 345: 136156.

[58]
Liu Z, Borodin A, Endres F. Energy Technol., 2022, 10(2): 2100907.

[59]
Tang J Q, Zhai B B, Liu J F, Ren W H, Han Y, Yang H, Chen Y S, Zhao C, Fang Y. Phys. Chem. Chem. Phys., 2021, 23(11): 6775.

[60]
Gu Y, Yan H, Wang W W, Zhang X G, Yan J W, Mao B W. Nano Lett., 2023, 23(21): 9872.

[61]
Gu Y, Chen H N, Wang W W, Yan H, Yan J W, Mao B W. ChemElectroChem, 2024, 11(4): e202300684.

[62]
Dong M Y, Zhang K Y, Wan X Y, Wang S L, Fan S K, Ye Z Z, Wang Y Q, Yan Y G, Peng X S. Small, 2022, 18(14): 2108026.

[63]
Chen N, Zhang H Q, Li L, Chen R J, Guo S J. Adv. Energy Mater., 2018, 8(12): 1702675.

[64]
Hu H, Li J, Ji X. Chem.-Eur. J., 2023, 30(5): e202302826.

[65]
Liu L W, Xue J Y, Liu Y, Lu S W, Weng S X, Wang Z C, Zhang F R, Fu D S, Xu J J, Wu X D. ACS Appl. Mater. Interfaces, 2024, 16(7): 8895.

[66]
Sha Y F, Yu T H, Dong T, Wu X L, Tao H Y, Zhang H T. ACS Appl. Energy Mater., 2021, 4(12): 14755.

[67]
Fong K D, Wang T S, Kim H K, Kumar R V, Smoukov S K. ACS Energy Lett., 2017, 2(9): 2014.

[68]
Li Y H, Sun Z J, Shi L, Lu S Y, Sun Z H, Shi Y C, Wu H, Zhang Y F, Ding S J. Chem. Eng. J., 2019, 375: 121925.

[69]
Li X W, Zheng Y W, Li C Y. Energy Storage Mater., 2020, 29: 273.

[70]
Zhu C J, Ning Y, Jiang Y Z, Li G J, Pan Q W. Polymers, 2022, 14(17): 3435.

[71]
Ma J Y, Ma X Y, Zhang H P, Chen F, Guan X H, Niu J P, Hu X P. J. Membr. Sci., 2022, 659: 120811.

[72]
Bao W, Hu Z Y, Wang Y Y, Jiang J H, Huo S K, Fan W Z, Chen W J, Jing X, Long X Y, Zhang Y F. Chem. Eng. J., 2022, 437: 135420.

[73]
Li S, Luo Z, Li L, Hu J G, Zou G Q, Hou H S, Ji X B. Energy Storage Mater., 2020, 32: 306.

[74]
Li S. Masteral Dissertation of Central South University, 2024.

(李硕. 中南大学硕士论文, 2024.).

[75]
Feng J W, Hu S G, Han B, Xiao Y L, Deng Y H, Wang Z Y. Energy Storage Sci. Technol., 2020, 9(6): 1629.

(冯建文, 胡时光, 韩兵, 肖映林, 邓永红, 王朝阳. 储能科学与技术, 2020, 9(6): 1629.).

[76]
Kim S, Lee T K, Kwak S K, Choi N S. ACS Energy Lett., 2022, 7(1): 67.

[77]
Lu Y Y, Tu Z Y, Archer L A. Nat. Mater., 2014, 13(10): 961.

[78]
Yang Q F, Hu J L, Meng J W, Li C L. Energy Environ. Sci., 2021, 14(6): 3621.

[79]
Sun H H, Liu J D, He J, Wang H P, Jiang G X, Qi S H, Ma J M. Sci. Bull., 2022, 67(7): 725.

[80]
Wang W, Ma W, Yang Q L, Lin Z K, Tang J, Wang M H, He Y, Fan C, Sun K N. Ind. Eng. Chem. Res., 2022, 61(30): 10883.

[81]
Huang J Q, Zhang H T, Yuan X D, Sha Y F, Li J, Dong T, Song Y T, Zhang S J. Chem. Eng. J., 2023, 464: 142578.

[82]
Ding F, Xu W, Graff G L, Zhang J, Sushko M L, Chen X L, Shao Y Y, Engelhard M H, Nie Z M, Xiao J, Liu X J, Sushko P V, Liu J, Zhang J G. J. Am. Chem. Soc., 2013, 135(11): 4450.

[83]
Gao T, Qian Z W, Chen H B, Shahbazian-Yassar R, Nakamura I. Mol. Syst. Des. Eng., 2022, 7(3): 260.

[84]
Zhang S J, Cheng B, Fang Y X, Dang D, Shen X, Li Z Q, Wu M, Hong Y, Liu Q B. Chin. Chem. Lett., 2022, 33(8): 3951.

[85]
Kim K, Park J, Jeong G, Yu J S, Kim Y C, Park M S, Cho W, Kanno R. ChemSusChem, 2019, 12(12): 2637.

[86]
Zhou X, Jiang H, Zheng H, Sun Y, Liang X, Xiang H F. J. Membr. Sci., 2020, 603: 117820.

[87]
Tsurumaki A, Rettaroli R, Mazzapioda L, Navarra M A. Appl. Sci., 2022, 12(14): 7318.

[88]
Zeng L C. Doctoral Dissertation of University of Science and Technology of China, 2017.

(曾林超. 中国科学技术大学博士论文, 2017.).

[89]
Budi A, Basile A, Opletal G, Hollenkamp A F, Best A S, Rees R J, Bhatt A I, O’Mullane A P, Russo S P. J. Phys. Chem. C, 2012, 116(37): 19789.

[90]
Ahmed F, Fang C, Li D F, Zhao Y Z, Liu G. ACS Appl. Energy Mater., 2023, 6(13): 7212.

[91]
Howlett P C, Brack N, Hollenkamp A F, Forsyth M, MacFarlane D R. J. Electrochem. Soc., 2006, 153(3): A595.

[92]
Winter M. Z. Phys. Chemie-Int. J. Res. Phys. Chem. Chem. Phys., 2009, 223(10/11): 1395.

[93]
Preibisch Y, Peschel C, Dohmann J F, Winter M, Nowak S. J. Electrochem. Soc., 2021, 168(2): 026501.

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