Electrolytes For Lithium Batteries Research Articles

Lithium Ion Battery Electrolytes Based on Deep Eutectic Solvents

Deep eutectic solvents (DESs) have emerged as an alternative to both common organic solvents and ionic liquids (ILs). DESs share physicochemical properties with ILs such as low vapor pressure, high thermal stability, while offering advantages such as low toxicity, lower cost, and ease of preparation. Moreover, DESs are attractive candidates for electrochemical applications due to their large voltage windows and solubility properties. DESs as a solvent class share a general composition of a hydrogen bond donor (HBD), typically a polyol, amide, or acid, and a hydrogen bond acceptor (HBA), usually a quaternary ammonium or phosphonium salt. At a specific molar composition of a HBD and HBA, the DES forms a eutectic mixture resulting in a large melting point depression.Despite being widely studied, the microscopic structures of DESs have remained largely uncharacterized. Herein, we present a multitechnique NMR study of ethaline (ethylene glycol + choline chloride). Pulsed field gradient diffusion, nuclear Overhauser effect spectroscopy (NOESY), 13C NMR relaxation experiments are deployed to sample a range of frequencies and modes of motion of the polyol and choline components of the DES. Generally, translational and rotational diffusion of polyols are more rapid than those of choline while short-range rotational motions observed from 13C relaxation indicate slow local motion of ethylene glycol at low choline chloride (ChCl) content.Additionally, we have investigated the solubility properties of several lithium salts (LiTFSI, LiFSI, LiBF4, and LiOAc) in these DESs and utilized the same suite of NMR techniques to understand how they act as solvents. One interesting observation is that the Li+ diffusivity exceeds that of the counterion for TFSI-, but not for FSI-. Finally, large changes in the structural organization of DESs that result from the presence of lithium salts may serve as a guide to the design of a new class of electrolytes for lithium-ion batteries.

Bulk SEI: Investigating the Instability of Li6PS5Cl at the Lithium Metal Anode

Among the multitude of lithium ion conducting materials, thiophosphate-based solid electrolytes (thio-SEs) attract great attention from academia and industry alike. Due to their high ionic conductivities and increased safety, thio-SEs – such as lithium argyrodite Li6PS5Cl – are considered suitable to be employed in solid-state batteries (SSBs). Thus, by substituting liquid organic electrolytes of lithium-ion batteries (LIBs), higher energy and power densities (in combination with lithium metal anodes (LMAs)) as well as simplified cell designs are promoted.[1] Unfortunately, one major drawback of thio-SEs is the inadequate reduction stability in contact with LMAs,[2] which impedes device-level applications and has to be overcome.Due to its thermodynamic instability, Li6PS5Cl is reduced upon contact with highly reactive lithium metal to a mixture of compounds, i.e., Li2S, Li3P, and LiCl. Thus, a so-called solid electrolyte interphase (SEI) is formed, which is predominantly ion-conducting. Its electronically insulating nature is suspected to limit the interphase formation and further growth.[3] Additionally, the chemical and structural properties differ from that of pure SE. Unfortunately, the SEI only evolves at the Li | Li6PS5Cl interface and its thickness is in the nanometer range.[4] Suitable methods to examine the characteristics of SEI layers are therefore scarce and mostly limited to surface sensitive characterization techniques.Here, we employ a novel approach to gain further insights into the nature of SEI layers of thiophosphate-based SE in contact with lithium metal, demonstrated with Li6PS5Cl as model solid electrolyte. Bulk material corresponding to the composition of the SEI is synthesized from SE and Li-metal in a direct manner and hence, examined in respect to different properties. The successful synthesis of bulk-phase SEI is confirmed by X-ray photoelectron spectroscopy measurements, validating the chemical composition. This is complemented by structural analysis. Electrochemical characterization (electrochemical impedance spectroscopy and Wagner-Hebb) is utilized to quantify the ionic and electronic conductivity of the obtained bulk material, respectively, and to further determine transport properties and SEI growth at the Li | Li6PS5Cl interface. The combined results of our studies allow comprehensive understanding of the SEI nature and offer boundary conditions to approximate the nanoscale properties of the SEI at the Li | Li6PS5Cl interface from bulk material synthesis and analysis.

Investigation of Sulfide-Based Solid Electrolytes (SSE) Sensitivity Towards Humidity

All-solid-state lithium-ion batteries (ASSBs) represent a new generation of energy storage tools containing only solid components. They are of great interest to researchers and manufacturers thanks to their high energy density, which makes them promising candidates for electric transport applications. Among different types of solid-state electrolytes for lithium-ion batteries (LIBs), sulfide-based electrolytes (SSEs) have several advantages, such as high ionic conductivity and malleability [1, 2]. However, one of their main drawbacks is a high sensitivity towards air humidity [3]. Fast reaction of the SSEs with water results in the degradation of their structure and release of toxic gas (H2S) when exposed to even low concentrations of humidity. This factor leads to significant process cost and safety issues associated with mass production of ASSBs with sulfide-based SEs.The purpose of the present work is to study in details reactivity of SSEs towards humidity by following two main directions: The development of a flow-through setup that allows a better identification and highly precise quantification of gases (H2S or others) generated during reaction between water (humidity) and commercial SSEs: this flow-through setup intends to solve problems usually encountered when using closed-type setups, which are the most used setups in the literature[3, 4]. These problems include over-concentration of detected gases and low reproducibility of measurements;Physico-chemical and electrochemical characterizations of pristine and humidity exposed-SSEs in order to reveal the main factors affecting sensitivity towards humidity and to understand the degradation mechanisms. First, the efficiency of the flow-through gas analysis setup developed had been validated: H2S detection curves obtained for commercial SSE powders (Li6PS5Cl, Li6PS5Br, Li7P3S11, Li3PS4, Li10GeP2S12) in contact with humid Argon (30 to 200 ppm H2O in Ar) are highly reproducible (see example in Fig. 1 and Table 1). Measurements conducted at different humidity levels allowed accessing kinetics of water-induced degradation reactions involved. SSE powders characterizations using XRD, Raman, XPS, SEM, EIS, granulometry before and after exposure to humidity provided an insight into degradation-related phenomena taking place: morphology deterioration, loss of structure and conductive structural groups, drastic increase of ionic resistance. A relationship between the structure of SSE and its reactivity towards water was found and described.Refs[1] Energy Storage Mater. 2018, 14, 58–74 ; [2] Nano Energy 2021, 83, 105858 ; [3] Solid State Ion. 2011, 182 (1), 116–119 ; [4] Chem. Mater. 2020, 32 (6), 2664–2672. Figure 1

Uncovering the Mechanism of Reactive Oxygen Species Scavenging by Organosilicon Lithium-Ion Battery Electrolyte Additives Using Fundamental Kinetic Analysis

Reactive oxygen species, among them radical anions, have been a subject of numerous investigations within the lithium-ion battery and lithium-air battery communities because of their capacity for destructive side reactions with both solvent and electrolyte components of their chemistries. Electrolyte additive components which can control these destructive species represent an opportunity for technical innovation. Such innovation, however, is hampered by a lack of fundamental understanding of the reactive pathways that these reactive compounds might take in systems as complex as battery electrolyte. With this in mind, we have explored a family of structurally related reactive oxygen species scavenging electrolyte additive molecules and quantified their fundamental reactivity with the superoxide radical anion. These experiments have also allowed us to determine the mechanism of action by which these additives scavenge radical anions, thereby supporting the rational design of future additives aimed at reactive oxygen species suppression in battery contexts.

Ionic liquids as battery electrolytes for lithium ion batteries: Recent advances and future prospects

Ionic liquids (ILs) have revolutionized the world ever since their discovery. Out of the immense possibilities of developing new materials, processes and mechanisms using ionic liquids, lies the great possibility of employing ionic liquids in the area of battery electrolytes. Battery technology is directly dependent on progress of battery electrolytes. In recent years there has been a fast growing demand of lithium ion batteries (LIBs) in mobile phones, laptops, electric vehicles and related high-voltage electrochemical applications. In the present article, our main focus is on ionic liquid based electrolytes – their types, advancements, progress and trends since late nineties up to the present times. In this endeavour, the role of fillers and solvent additives in enriching the electrochemical properties of electrolyte are clearly mentioned and emphasized. An attempt has also been made to bring out the future prospects for new beginners in the development of solid composite electrolytes employing ionic liquids.

Highly Conductive Polysiloxane Elastomers with Excellent Transparency, Resilience, and Stretchability.

Flexible transparent conductive materials show great potential in wearable electronics, flexible sensors, and so on. But the most used flexible conductive materials like hydrogels and ionogels suffer from evaporation and solvent leakage. For the application in these fields, integrated performances of preeminent resilience, transparency, stability, and conductivity that do not change with deformation are prerequisites. It is still challenging to handle the trade-off among these performances. Herein, a facile approach is established to balance these properties into one elastomer. Through the thiol-ene click reaction, mercaptopropyl-modified polydimethylsiloxane (mPDMS) is cross-linked and grafted by PEG-based macromonomers to prepare conductive elastomers. By anchoring with mPDMS through carbon-sulfur bonds, PEG can be evenly dispersed, resulting in ultratransparency (97%) and stable conductivity of as high as 1.68 × 10-2 S m-1, comparable to pure PEG/lithium salt conductivity. It also has a wide electrochemical stability window with a high voltage of 4.8 V. Moreover, the multibond network strategy is employed through grafting ligand 1-vinylimidazole to mPDMS to construct dynamic cross-links between Zn(II) and 1-vinylimidazol, bestowing excellent properties to the elastomers. Overall, elastomers with a well-balanced performance of high resilience, good conductivity, and ultratransparency are obtained, providing promising applications for soft electronics, lithium battery electrolytes, and flexible devices.

The Relationship between Ionic Conductivity and Solvation Structures of Localized High-Concentration Fluorinated Electrolytes for Lithium-Ion Batteries.

Localized high-concentration electrolytes (LHCEs) combine a diluent with a high-concentration electrolyte, offering promising properties. The ions, solvent, and diluent interact to form complex heterogeneous liquid structures, where high salt concentration clusters are embedded in the diluent. Optimizing LHCEs for desired electrolyte properties like high ionic conductivity, low viscosity, and effective solid electrolyte interphase (SEI) formation ability within the vast chemical and compositional design space requires deeper understanding and theoretical guidance. We investigated the structures and conductivities of LHCEs based on a fluorinated solvent with two different diluents at varying concentrations. 2,2,3,3-Tetrafluoropropyl trifluoroacetate (TFPTFA) enters the solvation cluster due to its stronger Li-ion interactions, whereas 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (TFETFE) enters only at extremely high diluent concentrations. The ionic conductivity increases with decreasing diluent concentrations, with a slope change during cluster percolation. Overall, TFETFE demonstrates higher effectiveness than TFPTFA, forming higher local salt concentration clusters and resulting in higher ionic conductivity.

Shock-tube CO measurements during the pyrolysis of ethylene carbonate

Ethylene carbonate (EC) is a key component of the flammable electrolyte in lithium-ion batteries. In this study, the pyrolysis of ethylene carbonate was investigated by measuring CO time histories near atmospheric pressure and in highly diluted conditions (0.999 He/Ar). The performance of a recent detailed chemical kinetics mechanism from Kanayama et al., 2022, was evaluated, and noticeable discrepancies were found, possibly indicating missing reaction pathways. A tentative model was proposed by merging the EC sub-mechanism from the Kanayama study with a recent model for linear carbonate pyrolysis from the authors (Grégoire et al., 2023). This tentative model includes the addition of several missing reactions for oxirane pyrolysis, and a couple of reactions for acetaldehyde and EC thermal decomposition were modified within their error uncertainties. The resulting model presents better predictions overall, but room for improvement remains. This study highlights the need to further study the pyrolysis chemistry of EC as well as acetaldehyde, which is a major intermediate component from EC pyrolysis under our conditions.

AlTiMgLiO medium entropy oxide additive for PEO-based solid polymer electrolytes in lithium ion batteries

Solid polymer electrolytes (SPE) have attracted considerable attention as electrolytes for solid-state batteries due to their toughness, high safety, and ionic conductivities that can be comparable with liquid electrolytes, especially at higher temperatures. However, polymers have low elastic moduli, which decrease at higher temperatures, limiting their ability to reduce dendrite formation. Mechanical blocking is one method of improving the interfacial layer and reducing dendritic growth but requires the elastic modulus of the polymer to be high enough to suppress lithium dendrites growth. Previous studies have focused on using unary metal oxides, which are limited by the percent of additives that can be included in the polymer before causing negative effects on electrochemical properties. In this study, we demonstrate a new strategy for improving the performance of polymers by synthesizing a multielement oxide (MEO) filler, AlTiMgLiO, to create a composite SPE with enhanced electrochemical performance. The synthesized AlTiMgLiO-containing SPE resulted in a voltage window of 0–6.18 V and a lithium transference number of 0.42. The overpotential voltage during galvanostatic cycling was reduced due to the improvements made to the morphology. The improvement of the interfacial layer reduced Li dendritic growth, resulting in a capacity of 99.68 mAh g−1 after 500 cycles, and a capacity retention of 78.69 %. The possible reasons for the improvement are discussed, providing a direction for future studies on the use of multielement materials as fillers in solid polymers electrolytes.

Polyethylene Oxide (PEO) Provides Bridges to Silica Nanoparticles to Form a Shear Thickening Electrolyte for High Performance Impact Resistant Lithium-ion Batteries.

The development of shear thickening electrolytes is proving to be pivotal in the quest for impact resistant lithium-ion batteries (LIBs). However, the high viscosity and poor stability associated with the need for high filler content has to date impeded progress. Here, this work reports a new type of polymer-bridged shear thickening electrolyte that overcomes these shortcomings, by utilizing the interaction between polymer chains and silica nanoparticles. The incorporation of polyethylene oxide (PEO) facilitates hydrocluster formation providing impact resistance with a filler content as low as 2.2 wt%. This low viscosity electrolyte has a high ionic conductivity of ≈5.1 mS cm-1 with excellent long-term stability, over 30 days. The effectiveness of this electrolyte in LIBs is demonstrated by excellent electrochemical performance and high impact resistance.

Electrochemical Characteristics of Elastic, Non-Polar Polyurethane-Based Polymer Gel Electrolyte for Separator-Less Lithium-Ion Batteries

Lithium-ion batteries (LIBs) have undergone countless enhancements in the past decade, mainly improvements in the basic components: electrodes, electrolyte, and separator. The separator, which acts as a physical barrier between the two electrodes, does not directly participate in the charge and energy storage.However, it is involved in the safety, form factor, and packaging density of the LIBs. While it occupies relatively less internal space than other components, the separator can be replaced with active materials such as gel polymer electrolytes (GPEs) which can serve as both the electrolyte and physical barrier between the electrodes. GPEs can potentially minimize the risks of liquid electrolytes, including flammability, electrolyte leakage, and explosion. Here we report the characteristics of polyurethane (PU)-based gel swollen in concentrated electrolyte solutions in separator-less cells. The poreless PU-based gel electrolyte conducts lithium ions, while preventing internal short-circuits. This is attributed to the presence of soft segments, which allow ion transport, and hard segments, which ensure mechanical integrity. Electrochemical measurements carried out in LFP half cells and symmetric Li cells revealed that the separator-less cells were operable between 0.2 C to 1 C rates, and that during long term cycling, the cells achieved stable Li electroplating overpotential, as the number of cycles increased.

Molecular Adsorption‐Induced Interfacial Solvation Regulation to Stabilize Graphite Anode in Ethylene Carbonate‐Free Electrolytes

AbstractMany organic solvents have excellent solution properties, but fail to serve as lithium‐ion batteries (LIBs) electrolyte solvents, due to their electrochemical incompatibility with graphite anodes. Herein, a new strategy is proposed to address this issue by introducing a surface‐adsorbed molecular layer to regulate the interfacial solvation structure without the alteration of electrolyte composition and properties. As a proof‐of‐concept study, it is demonstrated for the first time that the intrinsically incompatible propylene carbonate (PC)‐based electrolyte becomes completely compatible with graphite anodes by introducing a layer of adsorbed hexafluorobenzene (HFB) molecules to weaken the Li+‐PC coordination strength and facilitate the interfacial desolvation process. As a consequence, the graphite/ NCM811 pouch cells using the PC‐based electrolyte containing only 1 vol.% HFB demonstrate excellent long‐term cycling stabilities over 1150 cycles. This strategy is also proved to be applicable to other ethylene carbonate (EC)–free electrolytes, thus providing a new avenue for developing advanced LIB electrolytes.

Click-chemistry and ionic cross-linking induced double cross-linking ionogel electrolyte for flexible lithium-ion batteries

With the expansion of portable devices, high-security and flexible energy storage technologies are gaining popularity. However, because of the use of poisonous, flammable, and unstable organic liquid electrolytes in commercial lithium-ion batteries, they cannot provide sufficient protection for the safety and long-term life of portable devices. A thiolate click reaction and ion interaction are used to successfully create a double cross-linking ionogel electrolyte (DC-Ionogel) by sealing 1-ethyl-3methyimidazolium bis (trifluoromethyl) imide (EMIm(TFSI)) in a double cross-linked network. An ion cross-linking network and a covalent cross-linking network are interlaced in the double cross-linked network, which considerably increased the flexibility and stability of the ionogel electrolyte. As a result, DC-Ionogel outperformed in terms of flame retardancy and thermal dimensional stability and outperformed in terms of electrochemical performance, with higher room ionic conductivity (1.79 × 10−3S cm−1) and a broader electrochemical window (5 V). Due to its excellent performance, it is more likely to be used in flexible energy-storage devices.

3D Printing-Enabled Design and Manufacturing Strategies for Batteries: A Review.

Lithium-ion batteries (LIBs) have significantly impacted the daily lives, finding broad applications in various industries such as consumer electronics, electric vehicles, medical devices, aerospace, and power tools. However, they still face issues (i.e., safety due to dendrite propagation, manufacturing cost, random porosities, and basic & planar geometries) that hinder their widespread applications as the demand for LIBs rapidly increases in all sectors due to their high energy and power density values compared to other batteries. Additive manufacturing (AM) is a promising technique for creating precise and programmable structures in energy storage devices. This review first summarizes light, filament, powder, and jetting-based 3D printing methods with the status on current trends and limitations for each AM technology. The paper also delves into 3D printing-enabled electrodes (both anodes and cathodes) and solid-state electrolytes for LIBs, emphasizing the current state-of-the-art materials, manufacturing methods, and properties/performance. Additionally, the current challenges in the AM for electrochemical energy storage (EES) applications, including limited materials, low processing precision, codesign/comanufacturing concepts for complete battery printing, machine learning (ML)/artificial intelligence (AI) for processing optimization and data analysis, environmental risks, and the potential of 4D printing in advanced battery applications, are also presented.

Conductometric sensor for ppb-level lithium-ion battery electrolyte leakage based on Co/Pd-doped SnO2

Safety problem caused by the leakage of electrolyte in lithium-ion batteries (LIB) have become a critical hot issue. However, since the main components of LIB electrolyte, such as dimethyl carbonate (DMC), are volatile or redox, trace electrolyte leakage is difficult to detect. Therefore, in order to realize early detection of electrolyte leakage and real-time monitoring of LIB health, here we report a success of DMC gas detection by MOS sensor based on Co/Pd-doped SnO2 nanomaterial for LIB health monitoring. In detail, the sensor showed high response to DMC when compared to interfering gases. Especially, the sensor could detect DMC down to the ppb level (the response value of the 500 ppb DMC is about 1.6). The response and recovery time for 1 ppm DMC were about 66 s and 240 s, respectively. The response of the sensor was obvious even when the leakage levels were as low as only 0.1 μL electrolyte. Furthermore, in the simulated electrolyte leakage via LIB penetration experiment, the sensor successfully exhibited an instant response, which proved that this work effectively provides a new approach for LIB real-time health and safety monitoring.

Inorganic Composites Improving Conductivities of Solid Polymer Electrolytes for Lithium Batteries: A Review

AbstractFor high‐energy‐density lithium batteries, the research and development of solid‐state electrolytes is crucial. Inorganic‐organic composite electrolytes with high mechanical strength and ionic conductivity of inorganic ceramic electrolytes, as well as high interfacial compatibility of polymer electrolytes, have become a current research hotspot. Based on a brief discussion of lithium dendrite growth and Li+ ion transport mechanisms, this article provides a comprehensive review of the nanostructure design and performance of inorganic‐organic composite electrolytes in recent years, and focuses on the mechanism of homogeneous monolayer composite electrolytes and heterogeneous multilayer composite electrolytes to enhance the performance of electrolytes. In addition, the future prospect of inorganic‐organic composite electrolytes is discussed, providing practical guidance for researchers in this field.

Post-synthetic Covalent Organic Framework to Improve the Performance of Solid-State Li+ Electrolytes.

As a new class of crystalline materials, covalent organic frameworks (COFs) have long-range ordered channels and feasibility to functionalize. The well-arranged pores make it possible to contain and transport ions. Here, we designed a novel functionalized anionic COF-SS-Li by a post-synthetic method utilizing the Povarov reaction of BDTA-COF, anchoring -SO3- groups to the COF backbone and converting the imine linkage to a more stable quinoline unit. The grafted -SO3- groups and directional channels can promote the lithium-ion transport through a hopping mechanism. As a solid-state lithium-ion electrolyte, COF-SS-Li exhibits the conductivities of 9.63 × 10-5 S cm-1 at 20 °C and 1.28 × 10-4 S cm-1 at 40 °C and a wide electrochemical window of 4.85 V. The assembled Li|COF-SS-Li|Li symmetric cell can cycle stably for 600 h at 0.1 mA cm-2. Also, the Li|COF-SS-Li|LiFePO4 cell delivers an initial capacity of 117 mAh g-1 at 0.1 A g-1 and retains a capacity rate of 56.7% after 500 cycles. The research enriches the solid-state electrolytes for lithium-ion batteries.

Transport coefficients for ion and solvent coupling. The case of the lithium-ion battery electrolyte.

Transport properties are essential for the understanding and modeling of electrochemical cells, in particular complex systems like lithium-ion batteries. In this study, we demonstrate how a certain degree of freedom in the choice of variables allows us to efficiently determine a complete set of transport properties. We apply the entropy production invariance condition to different sets of electrolyte variables and obtain a general set of formulas. We demonstrate the application of these formulas to an electrolyte typical for lithium-ion batteries, 1M lithium hexafluoro-phosphate in a 1:1 wt. % mixture of ethylene and diethyl carbonates. While simplifications can be introduced, they provide inadequate predictions of conductivity and transport numbers, and we argue that a full matrix of Onsager coefficients is needed for adequate property predictions. Our findings highlight the importance of a complete set of transport coefficients for accurate modeling of complex electrochemical systems and the need for careful consideration of the choice of variables used to determine these properties.

Highly swollen ROMP-based gels

The leakage of organic solvent during the transportation and storage is one of the major threats to the environment. Networks/gels acting as the absorbing materials for organic solvents are the most promising solution for the organic solvent pollution. Here, we report the synthesis of highly swollen networks/gels in high yield (≥95%) via ring opening metathesis polymerization (ROMP) using Grubbs’ first generation catalyst/initiator (G1), a crosslinker (1,1′-(methylenedi-4,1-phenylene)bis-exo-7-oxanorbornenecarboximide) and monofunctional monomer/diluent (exo-N-phenyl-7-oxanorbornenecarboximide). The mesh size of the network was varied by keeping the concentration of monomer constant while changing the concentrations of crosslinker and G1 (initiator). The swelling capacity of the network in N,N-dimethylformamide (DMF) solvent increased from 41 to 53 and to 61 with the increase of theoretical mesh size (molar ratio of monomer to crosslinker) from 20 to 40 and to 60, respectively. By further increasing the mesh size from 60 to 80 there was no significant change in swelling capacities (63). Thus, the gel with the mesh size of 60 was selected for swelling capacity analysis in other polar organic solvents such as dimethyl sulfoxide (DMSO), dichloromethane (DCM), chloroform and lithium-ion battery electrolyte solution (1.0 M LiPF6 in ethylene carbonate (EC)/diethyl carbonate (DEC) = 50/50 (v/v)). They showed the decreased swelling capacity value from 61 to 57, 40, 31 and 5, respectively. For a controlled mesh size ROMP-based gel, we observed the highest swelling capacity values to date.

Recent Progress on Electrolyte Boosting Initial Coulombic Efficiency in Lithium‐Ion Batteries

AbstractThe initial Coulombic efficiency (ICE) of electrode materials is closely related to the energy density of lithium‐ion batteries (LIBs). However, some promising electrode materials for next generation LIBs suffer from low ICE, which inevitably hinders their practical application. Among the discovered modified strategies for LIBs, electrolyte optimization has attracted extensive attention due to its facile operation process. Herein, the role of ICE in LIBs is first analyzed. Subsequently, the recent progress on effective electrolyte optimization strategies for boosting ICE in LIB is summarized (including the optimization of lithium salt, salt concentration, solvent, and electrolyte additive). Finally, future research directions of electrolyte optimization for boosting ICE are proposed. This review provides valuable guidance for developing advanced electrolyte for LIBs.