Li Salt Research Articles

Grain-Boundary-Rich Interphases for Rechargeable Batteries.

The formation of stable interphases on the electrodes is crucial for rechargeable lithium (Li) batteries. However, next-generation high-energy batteries face challenges in controlling interphase formation due to the high reactivity and structural changes of electrodes, leading to reduced stability and slow ion transport, which accelerate battery degradation. Here, we report an approach to address these issues by introducing multicomponent grain-boundary-rich interphase that boosts the rapid transport of ions and enhances passivation toward prolonged lifespan. This is guided by fundamental principles of solid-state ionics and geological crystallization differentiation theory, achieved through improved solvation chemistry. Demonstrations showcase how the introduction of the interphase substantially impacts the Li-ion transport across the interphase and the electrode-electrolyte compatibility in cost-effective electrolyte solutions optimized with multiple Li salts. The resulting interphases feature microstructures rich in inorganic grain boundaries with a diverse array of nanosized grains, presenting enhanced Li-ion transport. Comprehensive analyses revealed that this realizes remarkable electrochemical stability over extended cycling periods by inhibiting electrode corrosion, thus holding promise for high-capacity thin-Li-metal, Si-based anodes, and even Li-free anodes when paired with high-capacity oxide cathodes. This work opens new avenues to customize protective interphases on high-capacity electrodes, promoting the development of batteries with the highest energy density using cost-effective electrolytes.

First‐Principles Molecular Dynamics Study on Reductive Stability of High Concentration Electrolyte on Zn Doped Cu Current Collector Surface

AbstractIn enhancing the lifespan of anode‐free Li metal batteries (AFLMBs), current collector (CC) engineering is crucial for achieving uniform and dendrite‐free lithium deposition. The commonly used copper (Cu) CC is unsatisfactory because of its poor lithiophilicity. Here, we consider Zn doping on the Cu CC surface (Zn−Cu) and explore the reductive stability of a high‐concentration electrolyte (HCE), consisting of 3.6 M Lithium Hexafluorophosphate (LiPF6) salt in a mixture of ethylene carbonate (EC) and diethylcarbonate (DEC), on the Zn−Cu (111) surface (HCE|Zn−Cu) using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations. The interfacial reactions in the HCE|Zn−Cu system are compared to those on the pristine Cu (111) surface (HCE|Cu). We have also studied the effect of electron‐rich environments on the decomposition mechanism of the HCE mixture on both the CC surfaces. It is found that the HCE mixture is electrochemically stable on both Cu and Zn−Cu surfaces in a neutral environment. However, under electron‐rich conditions, only one DEC molecule has decomposed upon contact with the Cu CC surface, while the two PF6− anion groups from Li salts have decomposed much faster (within 100 fs) when the HCE mixture interacts with the Zn−Cu surface. Our results indicate that Zn doping suppresses undesirable solvent decomposition and improves the quality of the solid electrolyte interphase (SEI) layer.

Ternary-salt localized high-concentration electrolyte: An ideal companion facilitating stable high-voltage cycling of lithium metal batteries

The strategic design of novel electrolytes to further enhance the overall performance of lithium metal batteries (LMBs) is highly desirable. Herein, combining the synergistic effect of multiple functional lithium (Li) salts and the solvation structure advantage of localized high-concentration electrolyte (LHCE), we propose a novel ternary-salt localized high-concentration electrolyte (TSLHCE) termed CETHER3-TDE that achieves broad electrochemical stability window, dendrite-free Li deposition, effective electrode interface protection, flame retardancy, and significantly enhances the cycling performance of LMBs. CETHER3-TDE enables Li (50 μm thickness) ||NMC622 (13.8 mg cm−2, 2.50 mAh cm−2) cell to achieve an impressive capacity retention of 83 % after 300 cycles with a cut-off voltage of 4.4 V. Additionally, it enables the Li (50 μm thickness) ||NMC811 (19.8 mg cm−2, 3.96 mAh cm−2) cell to achieve a capacity retention of 83.6 % after 170 cycles, under an ultrahigh cut-off voltage of 4.6 V. Furthermore, the Li metal pouch cell employing CETHER3-TDE, featuring a low negative/positive (N/P) capacity ratio of 1.33 and lean electrolytes of 2.3gAh−1, attains an energy density of 413 Wh kg−1 and maintains stable cycling at 4.6 V. Moreover, analysis conducted by Accelerating Rate Calorimeter has verified that CETHER3-TDE enhances both the thermal stability as well as the thermal runaway trigger temperature of LMBs, thereby substantially improving their safety. This work provides valuable insights for future research on multi-salt complex electrolyte system for practical application in high-energy-density and high safety LMBs.

Robust polymer electrolytes with fast ion-transport nanochannels constructed by carbon dots for long lifespan Li metal batteries

As an anode material in energy storage systems, Li metal has exceptional merits, including high specific capacity, low density, and low redox potential. However, challenges such as lithium dendrites and unstable solid electrolyte interphase (SEI) hinder the practical application of lithium metal batteries (LMBs). Solid polymer electrolytes (SPEs), notably PVDF-HFP, are expected to overcome the above problems because of their mechanical merits and safe features, but their limited ion transportation behaviors result in insufficient ionic conductivity at room temperature. Herein, we invent an approach to prepare high performance electrolytes composed by porous PVDF-HFP and functionalized carbon dots (CDs). Such porous PVDF-HFP polymer membranes are created by a subtle phase inversion process, possessing a sponge-like structure, vertical lithium-ion transport channels and CDs decorated surfaces, thus able to uptake the liquid electrolyte (LE) to form gel polymer electrolytes (GPEs). The CDs fillers are produced in large scale with adjustable surface states, which can enhance Li salts disassociation to release free Li ions. As a result, the optimal conductivity of the as-prepared GPEs at room temperature is up to 8.7 mS cm−1 and the lithium transference number reaches 0.64. Our GPEs endow Li symmetric batteries with very stable SEI and long cycling life over 2200 h, and help realize high capacities and retention rates of the LMBs using LiFePO4(LFP) or LiCoO2(LCO) cathodes.

Outer Helmholtz plane adsorption regulation to achieve low-concentration of pure propylene carbonate solvent electrolytes compatible with graphite anode

The low melting point and high polarity of propylene carbonate (PC) make it an ideal solvent for electrolytes of lithium-ion batteries (LIBs), but the incompatibility with graphite anode hinders the application. In the present study, a new method is developed to solve this problem from a new viewpoint. Introduction of saturated LiNO3 (0.14 mol L‒1) into pure PC electrolyte containing lithium salt with normal concentration (1.38 mol L‒1) leads to a perfect compatibility with graphite anode. Li/Graphite cell using this pure PC electrolyte shows a reversible capacity of 350.0 mAh g‒1 and a 200-cycle capacity retention of 96.3 %. Further mechanism study and theoretical computation indicate that the NO3‒ anions are adsorbed to outer Helmholtz plane of the electric double layer at the graphite anode interface. This changes the Li+ solvation structure in the electric double layer, facilitating the Li+ desolvation process hence resulting in high compatibility with the graphite anode. The most prominent advantage of the present strategy is that, because of the adsorption of NO3‒ anions to the outer Helmholtz plane, the compatibility with graphite anode could be improved by introduction of tiny amount of Li salt without large change of the bulk phase properties of the electrolyte. This work provides a new understanding of the compatibility from the viewpoint of outer Helmholtz plane, which might deliver new insights for the optimization of electrolytes for LIBs.

Tailoring Ce-Centered Metal-Organic Frameworks for Fast Li+ Transport in Composite Polymer Electrolyte.

Regulating metal nodes to innovate the metal-organic framework (MOF) structure is of great interest to boost the performance of MOFs-incorporated composite solid electrolytes. Herein, Ce4+ with a low-lying 4f orbital is selected as metal center to coordinate with organic ligand to prepare MOF of Ce-UiO-66. The unsaturated open metal sites and defected oxygen vacancies furnish Ce-UiO-66 with strengthened Lewis acidity, which promotes Ce-UiO-66 interacting effectively with both poly(ethylene oxide) (PEO) and Li salt anions. Accordingly, Ce-UiO-66 as additive fillers can be uniformly dispersed in PEO matrix to form an advanced composite solid-state electrolyte (Ce-UiO@PEO) with accelerated Li+ transport. The optimized Ce-UiO@PEO displays a boosted ionic conductivity of 4.20 × 10-4 S cm-1 and an improved Li+ transference number of 0.39 at 60 °C, which are highly comparable to those of other MOFs@PEO electrolytes. Combined with the mechanical and thermal stabilities, such a Ce-UiO@PEO electrolyte enables Li/Li symmetric and Li/LiFePO4 full cells with superior cycling stability and rate performance. The Ce-UiO@PEO electrolytes are of great potential to be applied in high-performance lithium metal batteries.

PVDF and PEO Catholytes in Solid‐State Cathodes Made by Conventional Slurry Casting

AbstractAll‐solid‐state Li batteries are desired for better safety and energy density than Li‐ion batteries. However, the lack of a penetrating liquid electrolyte requires a much different approach to the design of cathodes. The solid catholyte must enable good Li+ conduction, form good interfaces with active material particles, and have the strength to bind the cathode together during repeated volume changes. Catholyte formulation is often simply adapted from Li‐ion design principles, adding a Li salt to the PVDF binder. Here we show that such a PVDF binder at 10 wt % loading is a starved catholyte condition that compromises cell performance. By substituting a 70 : 30 blend of PVDF:PEO, performance is improved while maintaining nearly the same areal loading of LFP active material. Increasing the catholyte fraction to 16 % can also improve performance, but in this case the benefit of including PEO is lessened, with PVDF alone being an adequate catholyte. EIS analysis shows that PEO helps to form charge transfer interfaces at 10 % catholyte, but that its inclusion can degrade interfaces when there is ample catholyte at 16 %. It is also shown that catholyte agglomeration can impede bulk Li conduction, indicating that microstructural factors are of critical importance.

Localized High-Concentration Electrolyte for All-Carbon Rechargeable Dual-Ion Batteries with Durable Interfacial Chemistry.

Lithium-based rechargeable dual-ion batteries (DIBs) based on graphite anode-cathode combinations have received much attention due to their high resource abundance and low cost. Currently, the practical realization of the batteries is hindered by easy oxidation of the electrolyte at the cathode interface, and solvent co-intercalation at the anode-electrolyte interface. Configuration of a "solvent-in-salt" electrolyte with a high concentration of Li salt is expected to stabilize the electrolyte chemistry versus both electrodes, yet inevitably reduces the mobility of the solvated working ions and increases the cost of the electrolyte. Herein, we propose to build a localized high-concentration electrolyte by adding hydrofluoroether as the diluent to reduce the salt content while improving the solvation structure, allowing more anions to enter the inner solvation sheath. The new electrolyte helps to form uniform and thin interfaces, with elevated contents of inorganic fluorides, on both electrodes, which effectively suppress electrolyte oxidation at the cathode and optimize electrolyte-electrode compatibility at the anode while facilitating charge transfer across the interface. Consequently, the DIBs with graphite as anode and cathode operate for 3000 cycles and retain a high-capacity retention of 95.7%, highlighting the importance of stable interfacial chemistry in boosting the electrochemical performance of DIBs.

Localized High‐Concentration Electrolyte for All‐Carbon Rechargeable Dual‐Ion Batteries with Durable Interfacial Chemistry

Lithium‐based rechargeable dual‐ion batteries (DIBs) based on graphite anode‐cathode combinations have received much attention due to their high resource abundance and low cost. Currently, the practical realization of the batteries is hindered by easy oxidation of the electrolyte at the cathode interface, and solvent co‐intercalation at the anode‐electrolyte interface. Configuration of a “solvent‐in‐salt” electrolyte with a high concentration of Li salt is expected to stabilize the electrolyte chemistry versus both electrodes, yet inevitably reduces the mobility of the solvated working ions and increases the cost of the electrolyte. Herein, we propose to build a localized high‐concentration electrolyte by adding hydrofluoroether as the diluent to reduce the salt content while improving the solvation structure, allowing more anions to enter the inner solvation sheath. The new electrolyte helps to form uniform and thin interfaces, with elevated contents of inorganic fluorides, on both electrodes, which effectively suppress electrolyte oxidation at the cathode and optimize electrolyte‐electrode compatibility at the anode while facilitating charge transfer across the interface. Consequently, the DIBs with graphite as anode and cathode operate for 3000 cycles and retain a high‐capacity retention of 95.7%, highlighting the importance of stable interfacial chemistry in boosting the electrochemical performance of DIBs.

Application of an in vitro neuroinflammation model to evaluate the efficacy of magnesium-lithium alloys.

Mg-Li alloys can be promising candidates as bioresorbable Li-releasing implants for bipolar disorder and other neurodegenerative disorders. In order to compare the therapeutic efficacy of conventional Li salts and Li delivered through Mg-Li alloy extracts, we tested an in vitro model based on the neuroinflammation hypothesis of mood disorders (peripheral inflammation inducing neuroinflammation) wherein, a coculture of microglia and astrocytes was treated with conditioned medium from pro-inflammatory macrophages. Two alloys, Mg-1.6Li and Mg-9.5Li, were tested in the form of material extracts and well-known outcomes of Li treatment such as GSK3β phosphorylation (indirect flow cytometry) and influence on inflammation-related gene expression (qPCR) were compared against Li salts. This is the first study demonstrating that Li can increase the phosphorylation of GSK3β in glial cells in the presence of excess Mg. Furthermore, Mg-Li alloys were more effective than Li salts in downregulating IL6 and upregulating the neurotrophin GDNF. Mg had no antagonistic effects toward Li-driven downregulation of astrogliosis markers. Overall, the results provide evidence to support further studies employing Mg-Li alloys for neurological applications.

LiF-enriched interphase promotes Li+ desolvation and transportation enabling high-performance carbon anode under wide-range temperature

Li-ion batteries (LIBs) have made inroads into the electric vehicle area with high energy densities, but they still suffer from slow kinetics of Li+ limited by the graphite anode especially at high current density and low-temperature conditions. Sluggish de-solvation of Li+ at the electrode surface and slow Li+ transfer in solid electrolyte interphase (SEI) are main determining factors that restrict the fast-charging and low-temperature performance of graphite-based LIBs. Here, we construct the sodium lignosulfonate layer with abundant polar functional groups on the lithium-montmorillonite surface, which can make it simple for electrons transfer to promote in-situ formation of LiF-based SEI with high ionic conductivity. The thin and robust LiF-based SEI promotes the de-solvation of Li salts and Li+ transfer as proved by the comprehensive electrochemical studies and density functional theory (DFT) calculations. Consequently, a combination of excellent stability and fast-charging ability for LIBs at room and low temperatures is achieved. The designed anode shows the remarkable capacity of 1500 mAh/g at 0.1 A/g, which was 3–4 times better than the commercial graphite. At the high current density of 5 A/g, it can still keep stable with the capacity retention of 70 % after 7000 cycles. Besides, an impressive 70 % of their room-temperature capacity is attained at −10 °C and 150 mAh/g is achieved under the extremely low temperature of −40 °C. This study establishes the effective strategy to construct the LiF-rich interface on the surface of anode to improve the Li+ kinetics and stability of the battery.

Triboelectric Nanogenerators of the Li Salt of Adipic Acid-Incorporated Poly(vinyl alcohol) Composites Toward Biomechanical Motion Energy Harvesting and in Sports Application

Triboelectric Nanogenerators of the Li Salt of Adipic Acid-Incorporated Poly(vinyl alcohol) Composites Toward Biomechanical Motion Energy Harvesting and in Sports Application

Eliminating Hydrogen Fluoride through Piperidine‐Doped Separators for Stable Li Metal Batteries with Nickel‐Rich Cathodes

AbstractHydrofluoric acid (HF)‐induced electrode and interfacial structure degeneration poses a significant challenge for high‐voltage lithium metal batteries (LMBs). To address this issue, we propose a separator strategy that involves decorating a regular polyethylene (PE) separator with molecular sieves (TW) impregnated with piperidine (PI). The porous structure of the TW serves as a reaction chamber for PI and HF. As a result, the HF content in the controlled electrolyte with 500 ppm H2O (ELE‐500) is notably reduced when using TW@PI‐PE separators, thereby shielding nickel‐rich cathodes from HF etching. Simultaneously, due to the hydrolysis of Li salts, and the inertness of PI towards H2O, a uniform lithium fluoride (LiF)‐rich solid electrolyte interphase can form on the Li metal anode, further mitigating dendrite formation. The lifespan of the symmetric Li cell using the TW@PI‐PE separator is doubled in ELE‐500, exhibiting stable 500‐hour cycles at 3 mA cm−2 and 3 mAh cm−2. Additionally, with the effective limitation of transition metal (TM) dissolution, the 4.6‐V LMBs employing a LiNi0.8Co0.1Mn0.1O2 cathode maintain an 81 % capacity retention over 100 cycles, even in ELE‐1000. The innovative TW@PI system presented here offers a fresh perspective for future research aimed at eliminating HF in LMBs.

A review of recent developments in the design of electrolytes and solid electrolyte interphase for lithium metal batteries

AbstractLithium metal batteries offer a promising solution for high density energy storage due to their high theoretical capacity and negative electrochemical potential. However, implementing of these batteries faces challenges related to electrolyte instability and the formation of a solid electrolyte interphase (SEI) on the lithium (Li) metal anode. The decomposition of liquid electrolytes leading to the creation of the SEI emphasizes the significance of the type of Li salt, solvent, and additives designed and used, as well as their interactions during the formation of the SEI. For practical applications, ensuring both the reversibility of the Li metal anode and electrolyte stability at high voltages is crucial. In this review, we explore recent advancements in addressing these challenges through new designs of electrolytes and SEI engineering practices. Specifically, we investigate the effects of electrolyte systems, including carbonate‐based and ether‐based solutions, along with modifications to these electrolyte systems aimed at achieving a more stable interface with the Li metal anode. Additionally, we discuss various artificial SEI structures based on organic and inorganic components. By critically examining recent research in these areas, this review provides valuable insights into current state‐of‐the‐art strategies for enhancing the performance and safety of Li metal batteries.image

High-Energy-Density Lithium–Sulfur Battery Based on a Lithium Polysulfide Catholyte and Carbon Nanofiber Cathode

Li–S batteries are promising large-scale energy storage systems but currently suffer from performance issues; a major reason is the dissolution of polysulfides in electrolytes. To this end, we report a high-energy-density Lithium–Sulfur (Li–S) battery that combines a catholyte and a sulfur-free carbon nanofiber (CNF) cathode. The cathode was synthesized by carbonizing binder-free polyacrylonitrile (PAN) nanofibers, affording a high surface area. In the catholyte, added polysulfides acted as both conductive Li salts and active materials. Investigating the electrochemical performance of this concept in both Swagelok- and pouch-type cells afforded energy densities exceeding 3 mAh cm−2 at a discharge rate of 0.1 C. This combination could also be utilized in high-capacity pouch cells with capacities of up to 250 mAh g−1. Both cell types exhibited good cycle performance. Adding LiNO3 to the electrolyte suppressed the redox shuttle reactions. Moreover, the cathode being binder-free increased the energy density and simplified cathode fabrication. Characterizing the cathode before and after cycling revealed that deposition was reversible, and that cell reactions at least partially formed sulfur as the end product, resulting in high sulfur amounts in the cell. We expect our concept to greatly aid in the development of practically applicable Li–S cells.

Solid-State Lithium Batteries with In Situ Polymerized Acrylate-Based Electrolytes Capable of Electrochemically Stable Operation at 100 °C.

Solid polymer electrolytes (SPEs) typically consist of salts with mobile anions that could cause instabilities and parasitic side reactions in solid-state lithium (Li) batteries. To address this challenge, single-Li-ion conducting (SLIC) SPEs, where anions of Li salts are covalently attached to the polymer backbone, have been utilized to reduce the number of mobile anions. This approach improves the cationic transference number but is accompanied by a loss of ionic conductivity. In this work, we investigate a synergetic approach of using both a polymerizable SLIC salt and a conventional Li salt in a polymer matrix by in situ polymerization of the poly(propylene glycol) acrylate (PPGA) monomer. The synthesized hybrid SPEs show a high ionic conductivity of up to ∼2 × 10-4 S cm-1 and a relatively high Li-ion transference number of ∼0.4. With a significantly reduced fraction of mobile anions in the combined salt SPE, in situ polymerized SPE cells with a LiFePO4 (LFP) cathode achieve a stable performance for over 100 cycles at temperatures as high as 100 °C, which is unattainable with conventional Li salts or electrolytes. Furthermore, solid-state nuclear magnetic resonance spectra provide additional insights into differences in Li nucleus environments and emphasize a reduction in activation energy for hybrid SPEs due to their more open structure. This study opens the path for the fabrication of high-performance solid polymer Li batteries capable of operating at high temperatures using commercial battery fabrication equipment, as in situ polymerized acrylate-based polymers provide drop-in compatibility with conventional battery production, ease of acrylate polymerization, and inexpensive, facile SPE chemistry. We expect that further tuning of the acrylate-based SPE composition may allow further increases in its conductivity without sacrificing its electrochemical stability or mechanical properties.

Waterborne Polyurethane Micelles Reinforce PEO-Based Electrolytes for Lithium Metal Batteries.

Although solid polymer electrolytes have been developed for several decades, poly(ethylene oxide) (PEO) or polymers with ethoxy (EO) segments are still one of the most promising candidates for advanced batteries. The low ionic conductivity and lithium-iontransference number as well as the deterioration of mechanical properties after coupling with lithium salts restrict its further adoption. Herein, a serial of PEO-based composite electrolytes optimized by waterborne polyurethane are prepared via blend method. With the assistance of H2O, ionic type waterborne polyurethane assembles into flexible micelles, in which hydrophobic segments as the core and hydrophilic groups as the shell. Utilizing this feature of waterborne polyurethane, PEO and Li salt (LiTFSI) aqueous solution is slowly added to the organic solution of waterborne polyurethane to compoundin situ, and polymer composite electrolytes are fabricated. The multilevel (hydrogen bonds with different binding energy) and multiscale (deformation of flexible micelles) dynamic interaction endows the composite electrolyte with attractive mechanical properties. The assembled Li|Li symmetric battery with the molar ratio of EO to Li salts of 8:1 exhibits excellent cycling stability up to 800 h at 0.1 mA cm-2, and the assembled Li|LiFePO4battery can be stably cycled at 1C for >400 cycles.

Modeling High Concentration Bisalt-in-Sulfolane Electrolytes and the Observation of Ligand-Bridged Cation-Pair Complexes.

Despite the abundance of sodium over lithium in Earth's crust and the copious amounts of expensive lithium salt required to make Li-ion high-concentration electrolytes (HCEs), studies of HCEs made from sodium salts remain sparse. A comparative molecular-level study of Li- and Na-ion HCEs and mixed cation or bisalt HCEs in an organic solvent is missing. To fill this gap, we studied model HCEs of pure and mixed Li and Na salts of bis(fluorosulfonyl)amide (FSI) in sulfolane using a confluence of classical molecular dynamics (MD), ab initio MD (AIMD) simulations, and quantum chemical cluster calculations. While Li-ion HCEs display transport properties superior to those of Na-ion HCEs, the latter's performance can be considerably improved by replacing even 25% of Na-ions with Li-ions. While the effects of doping are largely systemic, a larger sensitivity of the identity of solvation shells of Li-ions to the Li-content of the HCE is observed; in contrast, those of Na-ions are more oblivious to it. Fascinating ligand-bridged, short-distance cation pairs observed in the classical MD simulations are confirmed using density functional theory-based AIMD simulations. Quantum chemical calculations in the gas phase reveal the thermodynamic stability of such cation pairs complexed with multiple anions and solvent molecules.

Unveiling the Reaction Mystery Between Lithium Polysulfides and Lithium Metal Anode in Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are widely regarded as one of the most promising next-generation high-energy-density energy storage devices. However, soluble lithium polysulfides (LiPSs) corrode Li metal and deteriorate the cycling stability of Li-S batteries. Understanding the reaction mechanism between LiPSs and Li metal anode is imperative. Herein, the reaction rate and products of LiPSs with Li metal anode, the composition and structure of the as-generated solid electrolyte interphase (SEI), and the mechanism of lithium nitrate (LiNO3) additives for inhibiting the corrosion reactions are systematically unveiled. Concretely, LiPSs react with Li metal anode more rapidly than Li salt and generate a Li2S-rich SEI. The Li2S-rich SEI is highly reactive with LiPSs, which exacerbates the formation of dendritic Li and the continuous corrosion of active Li. LiNO3 functions dominantly by modulating the solvation structure of LiPSs and inherently reducing the reactivity of LiPSs, rather than the conventional understanding of LiNO3 participating in the formation of SEI. This work reveals the reaction mechanism between LiPSs and Li metal anode and inspires rational regulating of the solvation structure of LiPSs for stabilizing Li metal anode in Li-S batteries.

Dual-Interphase-Stabilizing Sulfolane-Based Electrolytes for High-Voltage and High-Safety Lithium Metal Batteries.

High-voltage Li metal battery (HV-LMB) is one of the most promising energy storage technologies to achieve ultrahigh energy density. Nevertheless, electrolytes reported to date are difficult to simultaneously stabilize the Li metal anode and high-voltage cathode, especially without the assistance of expensive and corrosive high-concentration Li salts. Herein, a dual-interphase-stabilizing (DIS) and safe electrolyte that bypasses the high-concentration Li salt is reported. The electrolyte consists of high-flash-point sulfolane as solvent, molecular-orbital-engineered additives that enable stable B-F rich cathodic interphase, and unique C-F rich organic anodic interphase. The stable cycling of both Li metal anode and 4.75V-LiCoO2 cathode in the DIS electrolyte (> 500 cycles) is demonstrated. HV-LMB pouch cells of a high energy density (435Wh kg-1) can sustainably operate for more than 100 cycles. Moreover, the low cost and high thermal stability of the DIS electrolyte offer superior cost-effectiveness and safety for large-scale applications of HV-LMBs in the future.