image
Home Journals Progress in Chemistry
Progress in Chemistry

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

About  /  Aim & scope  /  Editorial board  /  Indexed  /  Contact  / 
Online first  /  Current issue  /  All issues  /  Top access  /  RSS

Progress in Chemistry >

2023 , Vol. 35 >Issue 10: 1534 - 1543

DOI: https://doi.org/10.7536/PC230319

Review

Advances and Challenges of Low-Temperature Electrolyte for Sodium-Ion Batteries

  • Guangxiang Zhang 1 ,
  • Chi Ma 1 ,
  • Chuankai Fu 1, 2 ,
  • Ziwei Liu 1 ,
  • Hua Huo 1, 2 ,
  • Yulin Ma , 1, 2, *
Expand
  • 1 School of Chemistry and Chemical Engineering, Harbin Institute of Technology,Harbin 150001, China
  • 2 State Key Laboratory of Space Power-Sources, Harbin Institute of Technology, Harbin 150001, China
*Corresponding author e-mail:

Received date: 2023-03-21

  Revised date: 2023-05-07

  Online published: 2023-06-12

Supported by

National Natural Science Foundation of China(22075064)

China Postdoctoral Science Foundation(2022M710950)

Fold

Abstract

Sodium-ion batteries have attracted ever-increasing attention in the fields of low-speed electric vehicles, and large-scale energy storage systems due to the advantages of abundant resources, low cost, high safety, and environmental friendliness. As one of the important components of sodium-ion batteries, the electrolyte is responsible for ion transfer between the cathode and the anode, which has a significant impact on cycle life, high-rate, safety, and self-discharge performance of sodium-ion batteries. However, it is difficult for sodium-ion batteries to perform well at low temperatures due to the decrease in ionic conductivity, the poor compatibility between the electrolyte and the electrode, the increase of desolvating power, and the poor properties of the electrode/electrolyte interphase. In this paper, the new understanding of the Na+ solvation structure in the electrolyte and the electrode/electrolyte interphase in recent years are summarized. And the design strategies of low-temperature electrolyte based on H-bond network breakdown, weak solvation, rapid reaction kinetics, and anion intervention are systematically analyzed. Finally, it is pointed out that the key to improving the low-temperature performance of sodium-ion batteries from the perspective of electrolyte is to understand the relationship between the Na+ solvation structure, the electrode/electrolyte interface properties, and the low-temperature performance of electrolyte.

Contents

1 Introduction

2 Working principle of sodium-ion batteries and limitation of low-temperature performance of the electrolyte

3 Research status of low-temperature electrolyte for sodium-ion batteries

3.1 Design strategies of low-temperature electrolyte based on the H-bond network breaking method

3.2 Design strategies of low-temperature electrolyte based on weakly solvating

3.3 Design strategies of low-temperature electrolyte based on rapid reaction kinetics

3.4 Design strategies of low-temperature electrolyte based on anionic intervention

3.5 Others

4 Conclusion and outlook

Key words： sodium-ion batteries; electrolyte; low-temperature; electrode/electrolyte interphase; solvation structure

Cite this article

Guangxiang Zhang , Chi Ma , Chuankai Fu , Ziwei Liu , Hua Huo , Yulin Ma . Advances and Challenges of Low-Temperature Electrolyte for Sodium-Ion Batteries[J]. Progress in Chemistry, 2023 , 35(10) : 1534 -1543 . DOI: 10.7536/PC230319

1 Introduction

The large-scale use of fossil fuels has brought serious pollution to the environment. With the increasing awareness of environmental protection, new green energy sources such as nuclear energy, geothermal energy and solar energy have been gradually developed. However, the energy provided by these new energy sources is discontinuous and unstable, which needs to be combined with energy storage systems. Lithium-ion batteries are widely used in energy storage, power tools, aerospace, military and other fields because of their high energy density, long cycle life and high safety[1⇓⇓~4]. However, with the vigorous development of lithium power, lithium metal resources have been exploited seriously, coupled with the small reserves of lithium metal resources in the world, the abundance of lithium in the earth's crust is only about 0.006%, and it is unevenly distributed in the world, which is seriously inconsistent with the growing market demand for energy storage[5]. Sodium-ion batteries have been re-examined because of their abundant sodium reserves, low cost, long life and high safety. The development of sodium-ion batteries can not only alleviate the pressure on the development of energy storage due to the lack of lithium resources, but also gradually replace lead-acid batteries and reduce environmental pollution. It is expected to become the mainstream power supply in the next generation of energy storage[6].
However, the problems such as the decrease of discharge capacity, the slowdown of charge-discharge rate and the decline of cycle life in low temperature environment have greatly limited the application of sodium-ion batteries in aerospace, submarine, high-latitude scientific exploration and other fields. Generally speaking, because of the good dissociation of sodium salt and the high ionic conductivity at the same electrolyte concentration, researchers generally believe that the low temperature performance of sodium ion batteries is better than that of lithium ion batteries.Therefore, it is of great significance to further explore the potential of low temperature performance of sodium-ion batteries, further improve the low temperature performance of sodium-ion batteries, and broaden the application temperature range of sodium ion batteries[7⇓~9][10⇓~12]. Similar to lithium-ion batteries, sodium-ion batteries are also composed of positive electrode, negative electrode, separator and electrolyte, among which electrolyte is considered to be one of the important factors restricting the stable operation of batteries at low temperatures[13]. Conventional low temperature electrolytes have the characteristics of low freezing point, low viscosity and high ionic conductivity. However, in recent years, with the in-depth study of electrolyte systems, the strategies to improve the low-temperature performance of electrolytes are not limited to conventional means, but focus on the regulation of the solvation structure of sodium ions in electrolytes and the improvement of the transport rate of sodium ions at the electrode/electrolyte interface. Therefore, it is very important to study the relationship between the solvation structure of electrolyte, the properties of electrode/electrolyte interface and the low temperature performance of electrolyte, and to design low temperature electrolyte with lower freezing point, high ionic conductivity, low desolvation energy and high interface stability based on these principles.
In this paper, the existing problems of electrolytes for sodium-ion batteries at low temperature are summarized, and the design strategies of electrolytes for sodium-ion batteries based on hydrogen bond network destruction, weak solvation, fast reaction kinetics and anion interaction are systematically analyzed, and the further development and application of electrolytes for sodium ion batteries are prospected.

2 The working principle of sodium-ion battery and the limitation of electrolyte performance at low temperature

Fig. 1 is a schematic diagram of the working principle of a sodium-ion battery and the main limiting factors of the low-temperature performance of the electrolyte. When the battery is charged, the Na+ is removed from the cathode material and enters the electrolyte through the cathode/electrolyte interface. In the liquid electrolyte, the Na+ first undergoes a solvation process to form a cluster surrounded by anions and solvent molecules, and then the cluster migrates to the negative electrode/electrolyte interface in the electrolyte, where it is further desolvated and separated from the encapsulation of anions and solvent molecules. At the same time, the same number of electrons produced by the positive electrode will be transferred to the negative electrode through the external circuit, and the Na+ will be combined with it and embedded into the negative electrode material, while the discharge process is reversed[14]. In the process of charge and discharge, solvent molecules or anions will decompose to form a solid electrode/electrolyte interface, and a positive electrode/electrolyte interface phase (CEI film) will be formed on the positive electrode side.The negative electrode/electrolyte interphase (SEI film) is formed on the negative electrode side. The two solid electrolytes will affect the intercalation and deintercalation of Na+, thus affecting the capacity, cycle life, rate, high and low temperature performance of the battery.
图1 钠离子电池工作原理及电解质低温性能的主要限制因素示意图

Fig.1 Schematic diagram of the operating principle of sodium-ion batteries and the main limiting factors for the low-temperature performance of the electrolyte

According to the working principle of sodium-ion battery, the kinetic behavior of sodium ion is closely related to the migration of sodium ion in the electrolyte and the properties of electrode/electrolyte interface, which are closely related to the composition of the electrolyte[15⇓⇓~18]. Appropriate electrolyte composition is not only conducive to accelerating the transport of ions in the electrolyte, but also conducive to the formation of a stable electrode/electrolyte interface, stabilizing the internal structure of the active material during cycling, and improving the electrochemical performance of the whole battery. However, in the low temperature environment, the properties of the electrolyte and the electrode/electrolyte interface at room temperature will deteriorate, resulting in the decline of the electrochemical performance of the battery.The reasons are shown in Figure 1: (1) The viscosity of the liquid electrolyte increases at low temperature, and the ionic conductivity decreases significantly, which causes a large concentration polarization and reduces the discharge capacity of the battery[19,20]; (2) The increase of the viscosity of the liquid electrolyte leads to the deterioration of the wettability between the electrolyte and the electrode, which makes the compatibility between the electrolyte and the electrode worse, thus leading to the increase of the interfacial impedance[21]; (3) At low temperature, the desolvation energy of Na+ increases, the desolvation process slows down, and the transport rate of Na+ at the electrode/electrolyte interface decreases, which is not conducive to the high-rate discharge of batteries[22]; (4) The conventional electrolyte can not fully support the redox reaction at low temperature, and the SEI formed at low temperature has poor stability and large interface impedance, which is not conducive to the stable cycle of the battery[23]. In addition, factors such as temperature and solution composition may lead to the transfer of control steps, which may change the key factors limiting the low temperature performance of sodium ions, such as the "series" steps of sodium ions escaping from the positive electrode, passing through the positive electrode/electrolyte interface, solvated ions diffusing in the solution, desolvation, and the negative electrode/electrolyte interface.

3 Research Status of Low Temperature Electrolyte for Sodium Ion Battery

Electrolytes for sodium-ion batteries can be divided into aqueous electrolytes, organic electrolytes, quasi-solid electrolytes and solid electrolytes. For any electrolyte type, the strategy of researchers to improve the low temperature performance of sodium-ion batteries from the electrolyte point of view is attributed to the improvement of the transport rate of sodium ions in the electrolyte and the electrode/electrolyte interface. In aqueous electrolytes, the stronger interaction between cosolvents or additives and water molecules can destroy the hydrogen bond network between water molecules, reduce the freezing point of electrolytes, and improve the transport rate of sodium ions in solvents at low temperatures. For organic liquid electrolytes, the conventional way is to select salts with low freezing point, low viscosity and high dissociation, while the related design strategy based on weak solvation, that is, to select solvents with appropriate dielectric constant, electrolytes with low salt concentration and electrolytes with local high concentration, further improves their low temperature performance[24⇓~26]. In addition, it is also an important direction to improve the low-temperature performance of electrolytes for sodium-ion batteries by adjusting the solvation structure of Na+ and the composition and structure of SEI through anion intervention to accelerate the interfacial reaction rate of Na+. In addition to all-solid-state electrolytes, the design strategies of low-temperature electrolytes based on the above principles can be classified into two main directions: improving the properties of electrode/electrolyte interface and adjusting the solvation structure of Na+ in electrolyte, which are summarized in Figure 2.
图2 钠离子电池低温电解质设计策略

Fig.2 Design strategies of low-temperature electrolyte for sodium-ion batteries

3.1 Design Strategy of Low Temperature Electrolyte Based on Breaking Hydrogen Bond Network Method

The strategy of improving the low temperature performance of electrolytes by breaking the hydrogen bond network is mainly used in aqueous sodium-ion batteries. In recent years, aqueous electrolytes have attracted attention because of their green, non-flammable and low cost[27,28]. However, the electrochemical performance of aqueous electrolytes is easily limited by the ambient temperature, mainly because the freezing point of water is 0 ℃, and below 0 ℃, the formation of hydrogen bond network between water molecules will lead to the condensation of electrolytes. At room temperature, the violent movement of water molecules makes these hydrogen bonds break and recombine continuously, but when the temperature is lower than 4 ℃, the kinetic energy of water molecules begins to decrease until it is lower than the energy required for hydrogen bond breakage, resulting in the frequency of hydrogen bond formation much higher than the frequency of hydrogen bond breakage, which leads to the solidification of electrolyte and reduces the electrochemical performance of electrolyte[21,29]. Therefore, it is particularly important to destroy the formation of hydrogen bond network in aqueous electrolyte and inhibit the solidification of electrolyte. Fig. 3 shows the design strategy proposed by some researchers to improve the low temperature performance of electrolyte by destroying the hydrogen bond network.
图3 基于破坏氢键网络方法的低温电解质设计策略. (a) χDMSO=0.3时溶剂结构模拟[30]; (b) NTP|H2O-DMSO|AC全电池在-50℃下的倍率性能[30], Copyright 2019, Wiley; (c) AC‖Na2CoFe(CN)6 全电池在-30℃下的电化学性能[33], Copyright 2022, Wiley

Fig.3 Design strategies of low-temperature electrolyte based on H-bond network breaking method. (a) Solvent structure simulation with χDMSO=0.3[30]; (b) High-rate performance of NTP|H2O-DMSO|AC full-cell at -50℃[30], Copyright 2019, Wiley; (c) Electrochemical performance of AC‖Na2CoFe(CN)6 full-cell at -30℃[33], Copyright 2022, Wiley.

Based on the fact that co-solvents or additives can break the hydrogen bonds between water molecules, thereby reducing the freezing point of the electrolyte, Tao et al. Reduced the freezing point of the solution by adding dimethyl sulfoxide (DMSO) to the solution[30]. In the H2O/DMSO mixed electrolyte, the interaction between the oxygen atoms in the S = O bond in DMSO and the hydrogen atoms in the O — H bond in water molecules forms a hydrogen bond network, which is quite stable and stronger than the hydrogen bond network between water molecules, and can prevent a large enough proportion of water molecules from crystallizing, thus destroying the hydrogen bond network within water molecules and lowering the freezing point. When the mole fraction of DMSO is 0.3, the ionic conductivity of the electrolyte is the highest at low temperature. Molecular dynamics (MD) simulation shows that DMSO molecules form hydrogen bonds with water molecules, and the hydrogen bond network between water molecules is destroyed (Figure 3A). The electrolyte was assembled with a NaTi2(PO4)3(NTP) cathode and a hard carbon (AC) anode as a full cell for testing, and still had good rate performance at − 50 ° C (Fig. 3B). In addition to DMSO, some alcohols or amides can also play a similar role as co-solvents for low-temperature electrolytes of sodium-ion batteries, such as methanol, ethylene glycol, glycerol, formamide (FA), etc[31][32].
Some inorganic salt cations are also hydrogen bond acceptors, which can destroy the interaction between hydrogen atoms and oxygen atoms between water molecules through the interaction between inorganic cations and hydrogen atoms, and then destroy the formation of hydrogen bond network. Jiao et al. Used CaCl2 as an additive, because Ca2+ is a hydrogen bond acceptor, the strong interaction between CaCl2 and water molecules destroys the original hydrogen bond network, which makes the freezing point of the solution lower[33]. It is worth noting that during the charge-discharge process, the Ca2+ does not participate in the electrochemical reaction, but only has the function of destroying the hydrogen bond network between water molecules. However, it is not the higher the content of CaCl2, the better the effect of low temperature. When the concentration of CaCl2 was 3.86 mol/kg, the freezing point of the solution was the lowest. The full cell was assembled with Na2CoFe(CN)6 as the positive electrode, activated carbon as the negative electrode, and an aqueous solution of 3.86 mol/L CaCl2+1 mol/L NaClO4 as the electrolyte, which could be stably cycled for 1000 times at a discharge capacity of nearly 80 mA/G at a current density of 1 C in a − 30 ° C environment (the charge-discharge curve is shown in Figure 3C).
The addition of low polarity cosolvent will reduce the solubility of electrolyte salt, which will lead to the nucleation and precipitation of electrolyte salt, and affect the electrochemical performance of electrolyte. Liu et al. Proposed a new type of composite hydrogel electrolyte, through the introduction of gas-phase SiO2, the SiO2 network is bonded with the S O 4 2 - in the electrolyte.The SiO2/ water/methanol mixed solvent forms a three-dimensional structure and can fix metastable Na2SO4, prevent the problem of reduced solubility of Na2SO4 electrolyte salt caused by methanol cosolvent, and obtain a lower freezing point[34]. Because the dense skeleton of the SiO2 in the hydrogel provides huge volume work on the electrolyte core, the Na2SO4 core cannot be enlarged; The stable hydrogen bond between water and methanol breaks the original hydrogen bond network between water molecules, thus lowering the freezing point of the whole hydrogel electrolyte. Therefore, the Na2SO4-SiO2 hydrogel electrolyte has high ionic conductivity at low temperature. A sodium ion full battery assembled by the hydrogel electrolyte, NaTi2(PO4)3 and activated carbon still has 65.05% of the room temperature capacity at a high current density of 0.13 a/G at -30 deg C.
To sum up, the method based on hydrogen bond network destruction is generally used to improve the low-temperature performance of aqueous electrolytes, which mostly contain polar cosolvents, such as dimethyl sulfoxide, ethylene glycol, methanol, formamide, etc., or additives with hydrogen bond acceptors (CaCl2, etc.). The freezing point of the electrolyte can be significantly reduced by destroying the original hydrogen bond network between water molecules through the formation of a hydrogen bond network between the cosolvent or additive and the water molecules, and the electrolyte can operate stably at a minimum temperature of -50 deg C.

3.2 Design Strategy of Low Temperature Electrolyte Based on Weak Solvation Method

In organic liquid electrolytes, the desolvation energy of sodium ions at the electrode/electrolyte interface can be reduced and the transport rate of sodium ions at the interface can be increased by weakening the interaction between metal cations and solvents.So as to effectively improve the low-temperature performance of the electrolyte, which has been proved to be effective not only in the design of lithium-ion low-temperature electrolytes, but also in sodium-ion batteries[35,36]. According to this principle, there are three improvement strategies: selecting solvents or cosolvents with appropriate dielectric constant, reducing the concentration of electrolyte salts, and using local high-concentration electrolytes.
In the process of electrolyte design, the dielectric constant and Donor number (DN) of the solvent are closely related to the difficulty of sodium salt dissolution, ion migration and ion desolvation. In general, the larger the dielectric constant of the solvent, the smaller the interaction between sodium ions and anions, and the easier the dissociation of sodium salts, resulting in more free ions, which is conducive to improving the ionic conductivity. However, solvents with high dielectric constant often have high viscosity, which makes it difficult for solvated sodium ions to migrate in the electrolyte and reduces the ionic conductivity. Therefore, from the ionic conductivity point of view, the selection of high-performance solvents requires an appropriate dielectric constant. DN value is another important parameter of solvent, which can measure the ability of solvent to donate electrons. Generally speaking, the larger the dielectric constant of the solvent, the larger the DN value, the easier the solvent to give electrons, the stronger the interaction between the solvent and sodium ions, and the more difficult it is for sodium ions to desolvate into the electrode at the electrode/electrolyte interface, resulting in a decrease in the transport rate of sodium ions at the electrode/electrolyte interface. Therefore, the selection of solvent needs to grasp the balance between anion-cation association and solvent/cation combination, and reduce the desolvation energy of sodium ions under the condition of ensuring sufficient conductivity. In recent years, low-temperature studies of organic liquid electrolytes have shown that ether solvents and carboxylate solvents not only have low viscosity and low freezing point, but also have appropriate dielectric constant, which can not only ensure sufficient conductivity in the electrolyte, but also obtain low desolvation energy of sodium ions, effectively improving the low-temperature performance of organic liquid electrolytes. The physicochemical properties of common ether solvents and carboxylic ester solvents are shown in Table 1[35⇓⇓⇓⇓⇓⇓~42].
表1 常见醚类溶剂[35⇓⇓~38]和羧酸酯类溶剂的物化性质[39⇓⇓~42]

Table 1 Physicochemical properties of common ether solvents[35⇓⇓~38] and carboxylate solvents[39⇓⇓~42]

Solvent Melting temperature
Tm/℃		 Boiling temperature
Tb/℃		 Viscosity η/
( m Pa·s) (25℃)		 Dielectric comstant
(25℃)
Ethylene glycol dimethyl ether (DME) -58 84 0.46 7.18
Diethylene glycol dimethyl ether (DEGDME) -64 162 1.06 7.4
Tetraethyleneglycol dimethyl ether (TEGDME) -46 111 3.39 7.53
1, 3-Dioxolane (DOL) -95 74 0.59 6.79
Tetrahydrofuran (THF) -108 65 0.46 7.52 (22℃)
Methyl acetate (MA) -84 57 0.36 6.68
Ethyl acetate (EA) -84 77 0.45 6.02
Ethyl propionate (EP) -74 99 0.5 5.76 (20℃)
Ethyl butyrate (EB) -93.3 121.3 — —
Wang et al. Used tetrahydrofuran as a solvent to improve the low temperature performance of sodium-ion batteries by taking advantage of the low Na+ desolvation energy of ether solvents[43]. Different from the conventional carbonate solvent, the tetrahydrofuran has a weak solvation effect, so that the tetrahydrofuran is combined with the Na+ more weakly, and the desolvation energy barrier of the Na+ is reduced; meanwhile, the combination between an anion and a sodium ion is stronger, and when the sodium ion enters the hard carbon negative electrode, the anion is preferentially reduced to obtain an SEI film in which NaF is uniformly distributed, so that the cycling stability of the battery is improved. At -20 ℃, the hard carbon anode can still maintain 95% of the room temperature capacity and can operate stably. Luo et al. Used the same strategy to weaken the affinity between sodium ions and solvent molecules by using a mixed solvent of diethylene glycol dimethyl ether and tetrahydrofuran with low salt concentration, and realized the rapid reaction of sodium ions at the positive and negative electrodes at low temperature, thus improving the cycle stability of sodium/sodium symmetric batteries at low temperature[44].
Carboxylate solvents are generally used as cosolvents, not directly as the main solvent. The addition of carboxylate cosolvents can greatly reduce the freezing point and viscosity of the electrolyte, and reduce the desolvation energy. Carboxylate solvents have been widely studied as low-temperature cosolvents for lithium-ion batteries. Smart et al. Used methyl butyrate and ethyl butyrate as cosolvents. When the content of methyl butyrate and ethyl butyrate in the solvent exceeded 75%, the reversible capacity of the assembled graphite ‖LiMn2O4 full battery reached 80% of the room temperature capacity at a current density of 0.05 C when charged and discharged at -60 ℃[45]. At present, the application of carboxylic ester solvents in the electrolyte of low-temperature sodium-ion batteries is still relatively small, and in the future, they can be used together with ester-based solvents to broaden the temperature range of sodium-ion batteries.
In addition to the solvent with proper dielectric constant, the weak interaction of Na+/ solvent can also be realized by adjusting the concentration of electrolyte salt. Compared with the electrolyte of lithium ion battery, the Stokes diameter of sodium ion in the electrolyte is smaller, and the conductivity of the electrolyte of sodium ion battery with the same concentration is higher, so the conductivity requirement can be met by using the electrolyte with lower concentration in the sodium ion battery. At the same time, when the electrolyte concentration decreases, the solvation structure of sodium ions will also change. Wang et al. Found that the diffusion behavior of Na+ at the electrode/electrolyte interface was different in electrolytes with different concentrations[46]. Normally used 1.0 mol/L electrolyte (NaClO4,EC∶PC=1∶1,5%vol FEC), a contact ion pair of C l O 4 - ions was observed with high binding energy, while in the electrolyte with a concentration as low as 0.3 mol/L, a weakly bonded Na+/ solvent structure was formed in the form of a solvent-separated ion pair with low binding energy, reduced desolvation energy of sodium ions, and reduced charge transfer impedance. At the same time, the use of weak solvated electrolyte can reduce the attack of corrosive substances such as HF and improve the cycle stability. With the 0. 3 mol/L low concentration electrolyte, the NVPF ‖ HC full cell has a specific discharge capacity of nearly 100 mAh/G at -25 ℃. Similarly, Wang et al. Used diethylene glycol dimethyl ether (DEGDME) as a solvent and used the strategy of low concentration of salt to reduce the energy barrier of the desolvation process of sodium ions, so that the low temperature performance and rate performance of the battery were improved, and the prepared soft-pack battery could be cycled tens of thousands of times at -20 ℃[47].
Compared with the high viscosity of high-concentration electrolyte, the local high-concentration electrolyte can adjust the solvation structure of metal cations by adding inert diluents to the electrolyte, weaken the interaction between Na+ and effective solvents, reduce the desolvation energy of cations, and improve the low temperature performance of the electrolyte under low viscosity. Luo et al. Used this strategy to design a fluorine-containing low-temperature electrolyte (0.8 mol/L NaPF6, fluoroethylene carbonate (FEC)/ethyl methyl carbonate (EMC)/hydrofluoroether (HFE) (volume ratio of 3:3:4))[22]. Among them, HFE is an insoluble solvent, whose main function is to change the solvation structure of sodium ions, weaken the affinity between sodium ions and effective solvents, and reduce the desolvation energy. The specific discharge capacity of the Na‖Na3V2(PO4)2F3 cell using the fluorine-containing low temperature electrolyte can reach 92.1 mAh/G even at -30 ° C and 30 C rate discharge.
To sum up, the method based on weak solvation is mostly used to improve the low temperature performance of organic liquid electrolytes, and ether solvents (such as diethylene glycol dimethyl ether, tetrahydrofuran), carboxylic ester solvents (such as methyl butyrate, ethyl butyrate, etc.) Or linear carbonate solvents (like EMC, DMC, etc.) with low freezing point and weak solvation ability are mostly used. On the premise of ensuring a certain ionic conductivity, by weakening the bonding strength between sodium ions and solvent molecules, the desolvation energy is reduced, the transmission of sodium ions at the electrode/electrolyte interface is accelerated, the low temperature performance of the electrolyte is effectively improved, and the electrolyte can be used in an environment of -60 deg C.

3.3 Design strategy of low temperature electrolyte based on fast reaction kinetics

Accelerating the transport of sodium ions at the electrode/electrolyte interface is an important measure to reduce the desolvation energy of sodium ions and improve the low temperature performance of electrolytes. Through cation-solvent co-intercalation and artificial interface layer construction, the energy barrier of cation transport at the electrode/electrolyte interface can be reduced, ion transport and charge transfer can be accelerated, and the low temperature performance of sodium-ion batteries can be improved[48,49].
In sodium-ion batteries, the behavior of graphite in ether electrolytes shows typical interfacial fast reaction kinetics, which is obviously different from its electrochemical behavior in lithium-ion batteries[48]. Graphite In the ether-based electrolyte, there is no desolvation process when sodium ions are intercalated into the negative electrode, but cations and solvents are co-intercalated into the graphite layer (Fig. 4, shown on the negative side of AG)[49⇓~51]. Xia et al. Also found this special behavior in the field of low-temperature sodium-ion battery research, dissolving 0.5 mol/L NaPF6 in DEGDME, and using artificial graphite as the negative electrode[52]. In the charging process, sodium ions are not intercalated into the graphite after removing the solvent shell, but are directly intercalated into the graphite layer by forming cation-solvent co-crosslinking products with solvent molecules, which avoids the slow desolvation process and accelerates the reaction rate. Many scholars believe that although the co-crosslinking product will change the graphite layer spacing, it will not destroy the reversibility of graphite anode[48,53,54].
图4 双离子电池工作原理[52], Copyright 2021, Wiely

Fig.4 Working principle of dual-ion battery[52], Copyright 2021, Wiely

Based on this, Xia et al. Prepared a dual-ion battery as shown in Figure 4 using polytriphenylamine organic cathode materials[52]. During the charge-discharge process, the polytriphenylamine cathode absorbs and desorbs anions, which avoids the influence of anions in the co-intercalation process of sodium ions and solvent. The AG ‖ polytriphenylamine full battery has ultrafast kinetic performance and can be charged to 80% within 150 s. The dual-ion battery has outstanding low-temperature performance, and the capacity can still maintain 61% of the room temperature even at -70 deg C.
In addition to graphite and hard carbon anodes, Wang et al. Used hydrogen titanate nanowires (HT-NWs) as a model and found that the regulation of oxygen defects on the structure of HT-NWs could trigger the unique co-intercalation behavior of Na+- solvent in ether-based electrolytes at -25 ° C by ex-situ infrared spectroscopy and X-ray diffraction[55]. The electrode reaction without precipitation process has a lower energy barrier and a faster reaction rate at the electrode/electrolyte interface. The Na+ precipitation process was eliminated by Na+- solvent co-intercalation, which effectively accelerated the Na+ diffusion rate, resulting in a defective HT-NW‖Na3V2(PO4)3 full cell exhibiting a high energy density of 119.1 Wh/kg and excellent stability (94.5% retention after 1000 cycles at 1.0 C). Wang et al. Utilized the alloying reaction of Bi anode with Na+ solvated structure (based on DEGDME solvent)[56]. As shown in Figure 5A, the solvated sodium ions can be directly intercalated into the Bi anode gap, and the sodium ions do not need the desolvation process, which accelerates the transport rate of sodium ions and improves the low-temperature performance of the full cell. The Bi ‖ NFPP @ C full cell has a discharge capacity of 200 mAh/G even in an environment of -70 ° C (Figure 5B, current density of 10 mA/G).
图5 (a) 溶剂化钠离子共插层过程[55]; (b) Bi‖NFPP@C电池在不同温度下的恒流充放电曲线[56], Copyright 2022, Wiely

Fig.5 (a) Co-intercalation process of solvated Na+[55]. (b) Galvanostatic charge/discharge curves of Bi‖NFPP@C cell at different temperat[56], Copyright 2022, Wiely.

In the field of lithium-ion battery research, the construction of artificial interface layer can improve the stability of the battery, improve the cycle life, and improve the high current charge and discharge endurance of the battery[57,58]. Electrolyte additive is an important means to construct artificial interface layer and improve the performance of electrode/electrolyte interface. Shu et al. Selected adiponitrile (AND) as an additive through the calculation of frontier molecular orbital energy, AND added it to 1 mol/L NaPF6 electrolyte in a series of proportions (the solvent was a mixed solvent of ethylene carbonate (EC)/propylene carbonate (PC)/diethyl carbonate (DEC) (volume ratio of 1 ∶ 1 ∶ 2).The results show that when ADN is 3%, the charge transfer resistance of the interface is the smallest and the stability is the highest, and the capacity of the positive electrode is increased by 13% at -20 ℃ compared with that without additives[59]. Yu et al. Generated an artificial heterogeneous interface composed of disodium selenide (Na2Se) and vanadium metal on the sodium metal surface by in situ spontaneous chemical reaction[60]. The related characterization shows that the interfacial layer has high sodium-affinity, excellent ionic conductivity and high Young's modulus, which can promote the adsorption and transport of Na+, effectively promote the desolvation of solvated Na+ in the environment as low as -40 ℃, and enable the Na@Na2Se‖Na3V2(PO4)3 to charge and discharge at a rate of 0. 5 C for more than 700 cycles at -40 ℃.

3.4 Design Strategy of Low Temperature Electrolyte Based on Anion Intervention

As an important part of the electrolyte of sodium-ion battery, sodium salt plays an important role in conducting ions between the positive and negative electrodes in the battery. As an important component of sodium salt, anion not only affects the dissociation of sodium salt, but also plays an important role in the solvation structure and the formation of solid electrode/electrolyte interface film.
Anions play an important role in regulating the solvation structure of sodium ions. High concentration electrolyte is often used to broaden the electrochemical window of aqueous electrolyte. However, high concentration electrolyte is easy to precipitate salt crystals at low temperature, which affects the electrochemical performance of electrolyte[61,62]. Reber et al. Used an asymmetric anion structure to improve the problem of electrolyte salting out in the electrolyte of a high-concentration aqueous sodium-ion battery at low temperatures[63]. Differential scanning calorimetry (DSC) experiments show that the sodium salt with asymmetric anion can reduce the liquidus of the electrolyte, and can effectively inhibit the nucleation and crystallization of the sodium salt itself while inhibiting the crystallization of water. After 500 cycles at current density of 0. 2 C at -10 ℃, the capacity retention rate of the Na3(VOPO4)2F‖NaTi2(PO4)3 with asymmetric anionic sodium salt can still reach 74%. The team also used Raman spectroscopy and molecular dynamics simulation to study the mechanism, and found that the different coordination structures between cations and anions lead to significant differences in intramolecular rotation.This bond rotation enabled by the FTFSI- anion asymmetry can disturb the surrounding solvation structure and hinder the close packing of anions and cations, which leads to the enhanced supercooling behavior of FTFSI- containing electrolytes[64].
Anions play an important role in regulating the composition and structure of the solid phase electrode/electrolyte interface. The electrode/electrolyte interface rich in anionic derivatives can be formed by regulating electrolyte salts, which can improve the cycle stability of the battery and reduce the interface charge transfer resistance. However, a single anion is sometimes difficult to meet the demand, resulting in the design strategy of double sodium salt electrolyte, whose basic principle is to use the different advantages or synergistic effect of the two salts to achieve the effect that a single sodium salt is difficult to achieve. Thenuwara et al. Used DEGDME as a solvent to test the coulombic efficiency of electrolytes (all 1 mol/L) prepared with NaSO3CF3(NaOTf), NaBF4, NaPF6, Na[(CF3SO2)2N](NaTFSI), and NaClO4 as a single salt, respectively, at low temperature, and found that the coulombic efficiency was the highest at low temperature when NaOTf electrolyte salt was used, but the average Coulombic efficiency was still less than 91%[65]. The double-salt electrolyte composed of 0.8 mol/L NaOTf and 0.2 mol/L NaBF4 showed excellent electrochemical performance at both room temperature and room temperature. Among them, the anions and cations of NaBF4 have strong binding and poor dissociation, although the anions are easy to form SEI rich in inorganic substances such as NaF, which is conducive to the rapid transport of sodium ions in the interfacial phase.However, the poor dissociation leads to the low ionic conductivity of the electrolyte, so NaOTf with better dissociation is used in the electrolyte, and the molar ratio of NaOTf is as high as 0.8, which is conducive to improving the ionic conductivity of the electrolyte. By combining the advantages of the two electrolytes, the low temperature performance of the electrolyte is effectively improved, and a battery assembled by adopting the double salt electrolyte and using Na3V2(PO4)3 as a positive electrode and sodium metal as a negative electrode can operate at a temperature as low as minus 60 deg C.
To sum up, the intrinsic characteristics of electrolyte salt have an important influence on the ionic conductivity, viscosity and other properties of electrolyte. NaClO4 or NaPF6 with good dissociation ability are often used in low temperature electrolytes, and fluorine-containing sodium salts, such as NaTFSI, NaTFSI, NaOTf, etc., are added in an appropriate proportion to form an anion-derived interface phase with low impedance and easy sodium ion transmission.

3.5 Other

In the process of large-scale application of sodium-ion batteries, solid electrolytes have attracted the attention of researchers because of their high safety[66⇓⇓⇓⇓~71]. Despite the low ionic conductivity of solid-state electrolytes, researchers are still trying to expand their temperature adaptability. Qi et al. Prepared a PFSA-Na membrane by replacing Li at the end of PFSA-Li polymer electrolyte with Na through a simple ion exchange method, which has high ionic conductivity (1.59×10-4S/cm,-15℃ at room temperature and 4.88×10-5S/cm at room temperature) and good thermal stability, and the prepared Na ‖ Prussian blue battery still has a certain cycle stability at a low temperature of -35 ℃[72]. Due to the serious interface problems of all-solid-state batteries, their long-term stable cycling at room temperature is still difficult to achieve, and their application at low temperature is a long way to go.
Quasi-solid electrolyte has the advantages of low flammability, high safety, high ionic conductivity, good compatibility with the electrode interface, and better cycle stability at low temperature than all-solid electrolyte. Zhang et al. Designed a multifunctional quasi-solid electrolyte with excellent flame retardancy and leakage resistance, which alleviated the problem of poor safety of liquid electrolyte to a certain extent, and also had excellent cycle stability and low temperature performance[73]. The MVE-alt-MA/BC composite membrane was immersed in 1. 0 mol/L NaClO4/ triethyl phosphate (TEP) -vinylene carbonate (VC) (volume ratio of 4 ∶ 6) electrolyte to obtain a quasi-solid electrolyte, which was assembled with Na3V2(PO4)3 cathode and sodium metal anode to form a battery with stable cycle, low electrode/electrolyte interface impedance and flame retardancy. Moreover, the quasi-solid-state battery has good low temperature performance, and the retention rate can reach 84. 8% after 50 cycles at 0. 1 C discharge at-10 ℃. Although quasi-solid electrolyte can improve the low temperature performance of solid electrolyte to a certain extent, it is still difficult to apply quasi-solid electrolyte to low temperature system.

4 Summary and Prospect

Sodium-ion batteries have the advantages of abundant resources, low cost and good safety, which can not only complement the advantages of lithium-ion batteries to alleviate the shortage of lithium resources, but also gradually replace lead-acid batteries to play an environmentally friendly role. Moreover, the potential low-temperature characteristics of sodium-ion batteries have prompted people to explore this advantage in depth, explore the reasons that restrict their stable operation at lower temperatures from the operation principle of sodium-ion batteries, and take measures to improve it accordingly, so as to meet the application needs of more harsh environments such as space, seabed, high latitudes and so on.
Electrolyte, as the medium of ion transmission between positive and negative electrodes, is one of the key factors restricting the stable operation of sodium-ion batteries at low temperatures. In the low temperature environment, due to the decrease of sodium ion transmission rate, the deterioration of electrode/electrolyte interface stability and the increase of polarization during charge and discharge, the discharge capacity of batteries is reduced and the cycle life is shortened, which is difficult to meet the use requirements. Previous researchers focused on the physical properties of electrolytes, such as low freezing point solvents and highly dissociative electrolyte salts, but these methods have limited improvement on the low temperature performance of electrolytes. With the development of research methods and testing methods, researchers have gradually realized the importance of the solvation structure of sodium ions in electrolytes and the transport of sodium ions at the electrode/electrolyte interface to improve the low temperature performance of electrolytes. First, the solvation structure of sodium ions not only affects the transport of sodium ions in the electrolyte, but also has an important impact on the ease of sodium ions leaving the electrolyte. By adjust that solvation structure of the sodium ion, the freezing point of the electrolyte can be effectively reduce, the desolvation energy of a Na+ is reduced, the transmission rate of the sodium ion at an electrode/electrolyte interface is accelerated, and the low-temperature performance of the electrolyte is improved. Secondly, the properties of the electrode/electrolyte interface are not only related to the rate of sodium ions leaving the solvent and entering the positive and negative electrode materials, but also closely related to the stability of the positive and negative electrode materials. By improving the properties of the electrode/electrolyte interface, the compatibility between the electrode and the electrolyte can be effectively improved, the transmission rate of sodium ions at the electrode/electrolyte interface can be accelerated, and the low temperature performance of the electrolyte can be improved.
In a word, in addition to the physical properties of electrolyte such as freezing point, viscosity and ionic conductivity, the solvation structure of sodium ions in electrolyte and the properties of electrode/electrolyte interface also have important effects on the low temperature performance of sodium ion batteries. On the one hand, a sodium ion solvation structure with weak desolvation energy is designed by matching a solvent with a proper dielectric constant and a sodium salt with a proper dissociation property and adjusting the molar ratio of the sodium salt in the electrolyte while ensuring that the ionic conductivity meets the requirement; On the other hand, the solid electrode/electrolyte interface with high Young's modulus, high adhesion, high stability, high sodium ion transport rate and low impedance can be derived by designing sodium salts and solvents with special fluorinated structures and adding appropriate additives, which is an important development direction of low-temperature electrolytes for sodium-ion batteries in the future.

References

Publishing order | Descend order by publishing year | Descend order by cited within
[1]
Sawicki M, Shaw L L. RSC Adv., 2015, 5(65): 53129.

[2]
Che H Y, Chen S L, Xie Y Y, Wang H, Amine K, Liao X Z, Ma Z F. Energy Environ. Sci., 2017, 10(5): 1075.

[3]
Yin C G, Ma Y L, Cheng X Q, Yin G P. Prog. Chem., 2013, 25(1): 54.

(尹成果, 马玉林, 程新群, 尹鸽平. 化学进展, 2013, 25(1): 54.).

[4]
Zhang L L, Ma Y L, Du C Y, Yin G P. Progress in Chemistry, 2014, 26 (4): 553.

(张玲玲, 马玉林, 杜春雨, 尹鸽平. 化学进展, 2014, 26 (4): 553.).

[5]
Li H, Wu C, Wu F, Bai Y. Acta Chim. Sinica., 2014, 72(01): 21.

(李慧, 吴川, 吴锋, 白莹. 化学学报, 2014, 72(01): 21.).

[6]
Lu Y, Zhao C L, Rong X H, Chen L Q, Hu Y S. Acta Phys. Sin., 2018, 67(12): 39.

(陆雅翔, 赵成龙, 容晓晖, 陈立泉, 胡勇胜. 物理学报, 2018, 67(12): 39.).

[7]
Wang Y M, Song S F, Xu C H, Hu N, Molenda J, Lu L. Nano Mater. Sci., 2019, 1(2): 91.

[8]
Guo X Y, Wang Z B, Deng Z, Wang B, Chen X, Ong S P. Chem. Mater., 2020, 32(16): 6875.

[9]
Vignarooban K, Kushagra R, Elango A, Badami P, Mellander B E, Xu X, Tucker T G, Nam C, Kannan A M. Int. J. Hydrog. Energy, 2016, 41(4): 2829.

[10]
Li P Y, Hu N Q, Wang J Y, Wang S C, Deng W W. Nanomaterials, 2022, 12(19): 3529.

[11]
Rodrigues M T F, Babu G, Gullapalli H, Kalaga K, Sayed F N, Kato K, Joyner J, Ajayan P M. Nat. Energy, 2017, 2(8): 17108.

[12]
Gupta A, Manthiram A. Adv. Energy Mater., 2020, 10(38): 2001972.

[13]
Feng Y, Zhou L M, Ma H A, Wu Z H, Zhao Q, Li H X, Zhang K, Chen J. Energy Environ. Sci., 2022, 15(5): 1711.

[14]
Pan H L, Hu Y S, Chen L Q. Energy Environ. Sci., 2013, 6(8): 2338.

[15]
Yin H, Han C J, Liu Q R, Wu F Y, Zhang F, Tang Y B. Small, 2021, 17(31): e2006627.

[16]
Li Y, Wu F, Li Y, Liu M Q, Feng X, Bai Y, Wu C A. Chem. Soc. Rev., 2022, 51(11): 4484.

[17]
Peljo P, Girault H H. Energy Environ. Sci., 2018, 11(9): 2306.

[18]
Eshetu G G, Elia G A, Armand M, Forsyth M, Komaba S, Rojo T, Passerini S. Adv. Energy Mater., 2020, 10(20): 2000093.

[19]
Wang M, Wang Q C, Ding X Y, Wang Y S, Xin Y H, Singh P, Wu F, Gao H C. Interdiscip. Mater., 2022, 1(3): 373.

[20]
Jaguemont J, Boulon L, DubÉ Y. Appl. Energy, 2016, 164: 99.

[21]
Zhao Y W, Chen Z, Mo F N, Wang D H, Guo Y, Liu Z X, Li X L, Li Q, Liang G J, Zhi C Y. Adv. Sci., 2021, 8(1): 2002590.

[22]
Zheng X Y, Gu Z Y, Fu J, Wang H T, Ye X L, Huang L Q, Liu X Y, Wu X L, Luo W, Huang Y H. Energy Environ. Sci., 2021, 14(9): 4936.

[23]
Yoo D J, Liu Q A, Cohen O, Kim M, Persson K A, Zhang Z C. ACS Appl. Mater. Interfaces, 2022, 14(9): 11910.

[24]
Pan K H, Lu H Y, Zhong F P, Ai X P, Yang H X, Cao Y L. ACS Appl. Mater. Interfaces, 2018, 10(46): 39651.

[25]
Xu K. Chem. Rev., 2004, 104(10): 4303.

[26]
Ponrouch A, Marchante E, Courty M, Tarascon J M, Palacín M R. Energy Environ. Sci., 2012, 5(9): 8572.

[27]
Yang M R, Luo J, Guo X N, Chen J C, Cao Y L, Chen W H. Batteries, 2022, 8(10): 180.

[28]
Bin D A, Wang F, Tamirat A G, Suo L M, Wang Y G, Wang C S, Xia Y Y. Adv. Energy Mater., 2018, 8(17): 1703008.

[29]
Errougui A, Lahmidi A, Chtita S, El Kouali M, Talbi M. J. Solut. Chem., 2023, 52(2): 176.

[30]
Nian Q S, Wang J Y, Liu S A, Sun T J, Zheng S B, Zhang Y, Tao Z L, Chen J. Angew. Chem. Int. Ed., 2019, 131(47): 17150.

[31]
Jiang P, Lei Z Y, Chen L A, Shao X C, Liang X M, Zhang J, Wang Y C, Zhang J J, Liu Z P, Feng J W. ACS Appl. Mater. Interfaces, 2019, 11(32): 28762.

[32]
Zhu K J, Sun Z Q, Li Z P, Liu P, Chen X C, Jiao L F. Energy Storage Mater., 2022, 53: 523.

[33]
Zhu K J, Li Z P, Sun Z Q, Liu P, Jin T, Chen X C, Li H X, Lu W B, Jiao L F. Small, 2022, 18(14): 2107662.

[34]
Cheng Y B, Chi X W, Yang J H, Liu Y. J. Energy Storage, 2021, 40: 102701.

[35]
Yao Y X, Chen X A, Yan C, Zhang X Q, Cai W L, Huang J Q, Zhang Q A. Angew. Chem. Int. Ed., 2021, 60(8): 4090.

[36]
Ma T, Ni Y X, Wang Q R, Zhang W J, Jin S, Zheng S B, Yang X A, Hou Y P, Tao Z L, Chen J. Angew. Chem. Int. Ed., 2022, 61(39): e202207927.

[37]
Cohn A P, Share K, Carter R, Oakes L, Pint C L. Nano Lett., 2016, 16(1): 543.

[38]
Kim H, Hong J, Park Y U, Kim J, Hwang I, Kang K. Adv. Funct. Mater., 2015, 25(4): 534.

[39]
Su D W, Kretschmer K, Wang G X. Adv. Energy Mater., 2016, 6(2): 1501785.

[40]
Lai P B, Huang B Y, Deng X D, Li J L, Hua H M, Zhang P, Zhao J B. Chem. Eng. J., 2023, 461: 141904.

[41]
Zhang J, Wang D W, Lv W, Qin L, Niu S Z, Zhang S W, Cao T F, Kang F Y, Yang Q H. Adv. Energy Mater., 2018, 8(26): 1801361.

[42]
Smart M C, Ratnakumar B V, Chin K B, Whitcanack L D. J. Electrochem. Soc., 2010, 157(12): A1361.

[43]
Tang Z, Wang H, Wu P F, Zhou S Y, Huang Y C, Zhang R, Sun D, Tang Y G, Wang H Y. Angew. Chem. Int. Ed., 2022, 61(18): e202200475.

[44]
Wang Z Q, Zheng X Y, Liu X Y, Huang Y Y, Huang L Q, Chen Y W, Han M, Luo W. ACS Appl. Mater. Interfaces, 2022, 14(36): 40985.

[45]
Smart M C, Ratnakumar B V, Behar A, Whitcanack L D, Yu J S, Alamgir M. J. Power Sources, 2007, 165(2): 535.

[46]
Deng L, Goh K, Yu F D, Xia Y, Jiang Y S, Ke W, Han Y, Que L F, Zhou J, Wang Z B. Energy Storage Mater., 2022, 44: 82.

[47]
Zheng Y Q, Sun M Y, Yu F D, Deng L, Xia Y, Jiang Y S, Que L F, Zhao L, Wang Z B. Nano Energy, 2022, 102: 107693.

[48]
Liu Q, Xu R G, Mu D B, Tan G Q, Gao H C, Li N, Chen R J, Wu F. Carbon Energy, 2022, 4(3): 458.

[49]
Wang D N, Du X Q, Zhang B A. Small Struct., 2022, 3(10): 2200078.

[50]
Castillo-Martínez E, Carretero-González J, Armand M. Angew. Chem. Int. Ed., 2014, 53(21): 5341.

[51]
Yin X P, Zhao Y F, Zhang J J. J. Electrochem., 2023, 1.

(殷秀平, 赵玉峰, 张久俊. 电化学, 2023, 1.).

[52]
Chen J W, Peng Y, Yin Y E, Fang Z, Cao Y J, Wang Y G, Dong X L, Xia Y Y. Angew. Chem. Int. Ed., 2021, 60(44): 23858.

[53]
Subramanyan K, Akshay M, Lee Y S, Aravindan V. Adv. Mater. Technol., 2022, 7(12): 2200399.

[54]
Jache B, Binder J O, Abe T, Adelhelm P. Phys. Chem. Chem. Phys., 2016, 18(21): 14299.

[55]
Sun M Y, Yu F D, Xia Y, Deng L, Jiang Y S, Que L F, Zhao L, Wang Z B. Chem. Eng. J., 2022, 430: 132750.

[56]
Li Z, Zhang Y, Zhang J H, Cao Y J, Chen J W, Liu H M, Wang Y G. Angew. Chem. Int. Ed., 2022, 61(13): e202116930.

[57]
Zheng X Y, Cao Z, Luo W, Weng S T, Zhang X L, Wang D H, Zhu Z L, Du H R, Wang X F, Qie L, Zheng H H, Huang Y H. Adv. Mater., 2023, 35(10): 2210115.

[58]
Hu A J, Chen W, Du X C, Hu Y, Lei T Y, Wang H B, Xue L X, Li Y Y, Sun H, Yan Y C, Long J P, Shu C Z, Zhu J, Li B H, Wang X F, Xiong J E. Energy Environ. Sci., 2021, 14(7): 4115.

[59]
Song X N, Meng T, Deng Y M, Gao A M, Nan J M, Shu D, Yi F Y. Electrochim. Acta, 2018, 281: 370.

[60]
Xia X M, Xu S T, Tang F, Yao Y, Wang L F, Liu L, He S N, Yang Y X, Sun W P, Xu C, Feng Y Z, Pan H G, Rui X H, Yu Y. Adv. Mater., 2023, 35(11): 2209511.

[61]
Jiang L W, Liu L L, Yue J M, Zhang Q Q, Zhou A X, Borodin O, Suo L M, Li H, Chen L Q, Xu K, Hu Y S. Adv. Mater., 2020, 32(2): e1904427.

[62]
Pahari D, Puravankara S. ACS Sustain. Chem. Eng., 2020, 8(29): 10613.

[63]
Reber D, Kühnel R S, Battaglia C. ACS Mater. Lett., 2019, 1(1): 44.

[64]
Reber D, Takenaka N, Kühnel R S, Yamada A, Battaglia C. J. Phys. Chem. Lett., 2020, 11(12): 4720.

[65]
Thenuwara A C, Shetty P P, Kondekar N, Wang C L, Li W Y, McDowell M T. J. Mater. Chem. A, 2021, 9(17): 10992.

[66]
Yu Z X, Shang S L, Seo J H, Wang D W, Luo X Y, Huang Q Q, Chen S R, Lu J, Li X L, Liu Z K, Wang D H. Adv. Mater., 2017, 29(16): 1605561.

[67]
Cai S, Meng W D, Tian H Q, Luo T T, Wang L, Li M, Luo J Y, Liu S. J. Colloid Interface Sci., 2023, 632: 179.

[68]
Pan J, Xu S M, Cai T X, Hu L L, Che X L, Dong W J, Shi Z Y, Rai A K, Wang N N, Huang F Q, Dou S X. Nano Lett., 2023, 23(8): 3630.

[69]
Lu Y, Alonso J A, Yi Q, Lu L, Wang Z L, Sun C W. Adv. Energy Mater., 2019, 9(28): 1901205.

[70]
Fertig M P, Skadell K, Schulz M, Dirksen C, Adelhelm P, Stelter M. Batter. Supercaps, 2022, 5(1): e202100131.

[71]
Li Z, Yu R, Weng S T, Zhang Q H, Wang X F, Guo X. Nat. Commun., 2023, 14: 482.

[72]
Du G Y, Tao M L, Li J E, Yang T T, Gao W, Deng J H, Qi Y R, Bao S J, Xu M W. Adv. Energy Mater., 2020, 10(5): 1903351.

[73]
Yang J F, Zhang M, Chen Z, Du X F, Huang S Q, Tang B, Dong T T, Wu H, Yu Z, Zhang J J, Cui G L. Nano Res., 2019, 12(9): 2230.

Options
Outlines

/

〈 〉