Liquid Polydimethylsiloxane Grafting to Enable Dendrite‐Free Li Plating for Highly Reversible Li‐Metal Batteries

Li‐metal is considered as the most promising anode material to advance the development of next‐generation energy storage devices owing to its unparalleled theoretical specific capacity and extremely low redox electrochemical potential. However, safety concerns and poor cycling retention of Li‐metal batteries (LMBs) caused by uncontrolled Li dendrite growth still limit their broad application. Herein, liquid polydimethylsiloxane (PDMS) terminated by –OCH₃ groups is proposed as a graftable additive to reinforce the anode dendrite suppression for LMBs. Such a grafting triggers the formation of a conformal hybrid solid electrolyte interphase (SEI) with increased fractions of LiF and Li–Si–O‐based moieties, which serve as a rigid barrier and ionic conductor for uniform Li‐ion flow and Li‐mass deposition. The grafting protected anode endows Li/Li symmetric cells with a long lifetime over 1800 h with a much smaller voltage gap (≈25 mV) between Li plating and stripping, than the naked anode. The coulombic efficiency values for Li/Cu asymmetric cells in carbonate electrolyte can reach up to 97% even at a high current density of 3 mA cm^?2 or high capacity up to 4 mAh cm^?2. The liquid PDMS additive shows advantage over solid siloxane additives with poor grafting ability in terms of Li surface compaction and SEI stabilization.     

High‐Power Lithium Metal Batteries Enabled by High‐Concentration Acetonitrile‐Based Electrolytes with Vinylene Carbonate Additive

To enable next‐generation high‐power, high‐energy‐density lithium (Li) metal batteries (LMBs), an electrolyte possessing both high Li Coulombic efficiency (CE) at a high rate and good anodic stability on cathodes is critical. Acetonitrile (AN) is a well‐known organic solvent for high anodic stability and high ionic conductivity, yet its application in LMBs is limited due to its poor compatibility with Li metal anodes even at high salt concentration conditions. Here, a highly concentrated AN‐based electrolyte is developed with a vinylene carbonate (VC) additive to suppress Li⁺ depletion at high current densities. Addition of VC to the AN‐based electrolyte leads to the formation of a polycarbonate‐based solid electrolyte interphase, which minimizes Li corrosion and leads to a very high Li CE of up to 99.2% at a current density of 0.2 mA cm^‐2. Using such an electrolyte, fast charging of Li||NMC333 cells is realized at a high current density of 3.6 mA cm^‐2, and stable cycling of Li||NMC622 cells with a high cathode loading of 4 mAh cm^‐2 is also demonstrated.     

Highly‐Cyclable Room‐Temperature Phosphorene Polymer Electrolyte Composites for Li Metal Batteries

Despite significant interest toward solid‐state electrolytes owing to their superior safety in comparison to liquid‐based electrolytes, sluggish ion diffusion and high interfacial resistance limit their application in durable and high‐power density batteries. Here, a novel quasi‐solid Li⁺ ion conductive nanocomposite polymer electrolyte containing black phosphorous (BP) nanosheets is reported. The developed electrolyte is successfully cycled against Li metal (over 550 h cycling) at 1 mA cm^?2 at room temperature. The cycling overpotential is dropped by 75% in comparison to BP‐free polymer composite electrolyte indicating lower interfacial resistance at the electrode/electrolyte interfaces. Molecular dynamics simulations reveal that the coordination number of Li⁺ ions around (trifluoromethanesulfonyl)imide (TFSI^?) pairs and ethylene‐oxide chains decreases at the Li metal/electrolyte interface, which facilitates the Li⁺ transport through the polymer host. Density functional theory calculations confirm that the adsorption of the LiTFSI molecules at the BP surface leads to the weakening of N and Li atomic bonding and enhances the dissociation of Li⁺ ions. This work offers a new potential mechanism to tune the bulk and interfacial ionic conductivity of solid‐state electrolytes that may lead to a new generation of lithium polymer batteries with high ionic conduction kinetics and stable long‐life cycling.     

Design of a Multifunctional Interlayer for NASCION‐Based Solid‐State Li Metal Batteries

NASCION‐type Li conductors have great potential to bring high capacity solid‐state batteries to realization, related to its properties such as high ionic conductivity, stability under ambient conditions, wide electrochemical stability window, and inexpensive production. However, their chemical and thermal instability toward metallic lithium (Li) has severely hindered attempts to utilize Li as anode material in NASCION‐based battery systems. In this work, it is shown how a tailored multifunctional interlayer between the solid electrolyte and Li anode can successfully address the interfacial issues. This interlayer is designed by creating a quasi‐solid‐state paste in which the functionalities of LAGP (Li_1.5Al_0.5Ge_1.5(PO₄)₃) nanoparticles and an ionic liquid (IL) electrolyte are combined. In a solid‐sate cell, the LAGP‐IL interlayer separates the Li metal from bulk LAGP and creates a chemically stable interface with low resistance (≈5 Ω cm²) and efficiently prevents thermal runaway at elevated temperatures (300 °C). Solid‐state cells designed with the interlayer can be operated at high current densities, 1 mA cm^?2, and enable high rate capability with high safety. Here developed strategy provides a generic path to design interlayers for solid‐state Li metal batteries.     

Intercalated Electrolyte with High Transference Number for Dendrite‐Free Solid‐State Lithium Batteries

Solid‐state lithium (Li) batteries using solid electrolytes and Li anodes are highly desirable because of their high energy densities and intrinsic safety. However, low ambient‐temperature conductivity and poor interface compatibility of solid electrolytes as well as Li dendrite formation cause large polarization and poor cycling stability. Herein, a high transference number intercalated composite solid electrolyte (CSE) is prepared by the combination of a solution‐casting and hot‐pressing method using layered lithium montmorillonite, poly(ethylene carbonate), lithium bis(fluorosulfonyl)imide, high‐voltage fluoroethylene carbonate additive, and poly(tetrafluoroethylene) binder. The electrolyte presents high ionic conductivity (3.5 × 10^?4 S cm^?1), a wide electrochemical window (4.6 V vs Li⁺/Li), and high ionic transference number (0.83) at 25 °C. In addition, a 3D Li anode is also fabricated via a facile thermal infusion strategy. The synergistic effect of high transference number intercalated electrolyte and 3D Li anode is more favorable to suppress Li dendrites in a working battery. The solid‐state batteries based on LiFePO₄ (Al₂O₃ @ LiNi_0.5Co_0.2Mn_0.3O₂), CSE, and 3D Li deliver admirable cycling stability with discharge capacity 145.9 mAh g^?1 (150.7 mAh g^?1) and capacity retention 91.9% after 200 cycles at 0.5 C (92.0% after 100 cycles at 0.2 C) at 25 °C. This work affords a splendid strategy for high‐performance solid‐state battery.     

Printable Solid Electrolyte Interphase Mimic for Antioxidative Lithium Metal Electrodes

Despite the ever‐growing demand for Li metals as next‐generation Li battery electrodes, little attention has been paid to their oxidation stability, which must be achieved for practical applications. Here, a new class of printable solid electrolyte interphase mimic (pSEI) for antioxidative Li metal electrodes is presented. The pSEI (≈1 µm) is directly fabricated on a thin Li metal electrode (25 µm) by processing solvent‐free, UV polymerization‐assisted printing, exhibiting its manufacturing simplicity and scalability. The pSEI is rationally designed to mimic a typical SEI comprising organic and inorganic components, in which ethoxylated trimethylolpropane triacrylate and diallyldimethylammonium bis(trifluoromethanesulfonyl)imide are introduced as an organic mimic (acting as a moisture‐repellent structural framework) and inorganic mimic (allowing facile Li‐ion transport/high Li⁺ transference number), respectively. Driven by the chemical/architectural uniqueness, the pSEI enables the thin Li metal electrode to show exceptional antioxidation stability and reliable full cell performance after exposure to humid environments.     

Dynamic Ion Sieve as the Buffer Layer for Regulating Li+ Flow in Lithium Metal Batteries

How to realize uniform Li⁺ flow is the key to achieve even Li deposition for lithium metal batteries (LMBs). In this study, a concept of dynamic ion sieve is proposed to design the buffer layer nearby Li anode surface to regulate Li⁺ spatial arrangement by introducing tributylmethylphosphonium bis(trifluoromethanesulfonyl)imide (TMPB) into the carbonate electrolyte. The buffer layer induced by TMP⁺ can adjust the velocity of arriving solvated Li⁺ that gives solvated Li⁺ sufficient time to redistribute and accumulate on Li anode surface, resulting in a uniform and higher concentrated Li⁺ flow. Besides, TFSI⁻ can participate in the generation of inorganic component-rich solid electrolyte interphase (SEI) with Li₃N, which can facilitate the Li⁺ conductivity of SEI. Consequently, the stable and uniform Li deposition can be obtained, achieving the excellent cycling performance up to 1000 h at 0.5 mA cm⁻² in the Li||Li symmetric cell. Besides, the Li||NCM622 full cell also possesses excellent cycling stability with a high-capacity retention rate of 66.7% after 300 cycles.     

Tuning a Solvation Structure of Lithium Ions Coordinated with Nitrate Anions through Ionic Liquid-Based Solvent for Highly Stable Lithium Metal Batteries

Rational design of promising electrolyte is considered as an effective strategy to improve the cycling stability of lithium metal batteries (LMBs). Here, an elaborately designed ionic liquid-based electrolyte is proposed that is composed of lithium bis(trifluoromethanesulfonyl)imide as the lithium salt, 1-ethyl-3-methylimidazolium nitrate ionic liquid ([EMIm][NO₃] IL) and fluoroethylene carbonate (FEC) as the functional solvents, and 1,2-dimethoxyethane (DME) as the diluent solvent. Using [EMIm][NO₃] IL as the solvent component facilitates a special Li⁺-coordinated NO₃⁻ solvation structure, which enables the continues electrochemical reduction of solvated NO₃⁻ and the formation of remarkably stable and conductive solid electrolyte interface. With FEC as another functional solvent and DME as the diluent solvent, the formulated electrolyte delivers high oxidative stability and ionic conductivity, and endows improved electrochemical reaction kinetics. Therefore, the formulated electrolyte demonstrates exceedingly reversible and stable Li stripping/plating behavior with high average Coulombic efficiency (98.8%) and ultralong cycling stability (3500 h). Notably, the high-voltage Li|LiNi_0.8Co_0.1Mn_0.1O₂ full cell with IL-based electrolyte exhibits enhanced cyclability with a capacity retention of 65% after 200 cycles under harsh conditions of low negative/positive ratio (3.1) and lean electrolyte (2.5 µL mg⁻¹). This study creates the first NO₃⁻-based ionic liquid electrolyte and evokes the avenue for practical high-voltage LMBs.     

Solid‐State Plastic Crystal Electrolytes: Effective Protection Interlayers for Sulfide‐Based All‐Solid‐State Lithium Metal Batteries

All‐solid‐state lithium metal batteries (ASSLMBs) have attracted significant attention due to their superior safety and high energy density. However, little success has been made in adopting Li metal anodes in sulfide electrolyte (SE)‐based ASSLMBs. The main challenges are the remarkable interfacial reactions and Li dendrite formation between Li metal and SEs. In this work, a solid‐state plastic crystal electrolyte (PCE) is engineered as an interlayer in SE‐based ASSLMBs. It is demonstrated that the PCE interlayer can prevent the interfacial reactions and lithium dendrite formation between SEs and Li metal. As a result, ASSLMBs with LiFePO₄ exhibit a high initial capacity of 148 mAh g^?1 at 0.1 C and 131 mAh g^?1 at 0.5 C (1 C = 170 mA g^?1), which remains at 122 mAh g^?1 after 120 cycles at 0.5 C. All‐solid‐state Li‐S batteries based on the polyacrylonitrile‐sulfur composite are also demonstrated, showing an initial capacity of 1682 mAh g^?1. The second discharge capacity of 890 mAh g^?1 keeps at 775 mAh g^?1 after 100 cycles. This work provides a new avenue to address the interfacial challenges between Li metal and SEs, enabling the successful adoption of Li metal in SE‐based ASSLMBs with high energy density.     

Enhanced Cycling Stability of Rechargeable Li–O2 Batteries Using High‐Concentration Electrolytes

The stability of electrolytes against highly reactive, reduced oxygen species is crucial for the development of rechargeable Li–O₂ batteries. In this work, the effect of lithium salt concentration in 1,2‐dimethoxyethane (DME)‐based electrolytes on the cycling stability of Li–O₂ batteries is investigated systematically. Cells with highly concentrated electrolyte demonstrate greatly enhanced cycling stability under both full discharge/charge (2.0–4.5 V vs Li/Li⁺) and the capacity‐limited (at 1000 mAh g^?1) conditions. These cells also exhibit much less reaction residue on the charged air‐electrode surface and much less corrosion of the Li‐metal anode. Density functional theory calculations are used to calculate molecular orbital energies of the electrolyte components and Gibbs activation energy barriers for the superoxide radical anion in the DME solvent and Li⁺–(DME) _n solvates. In a highly concentrated electrolyte, all DME molecules are coordinated with salt cations, and the C–H bond scission of the DME molecule becomes more difficult. Therefore, the decomposition of the highly concentrated electrolyte can be mitigated, and both air cathodes and Li‐metal anodes exhibit much better reversibility, resulting in improved cyclability of Li–O₂ batteries.     

An Ultrarobust Composite Gel Electrolyte Stabilizing Ion Deposition for Long‐Life Lithium Metal Batteries

Lithium metal batteries (LMBs) possessing ultrahigh energy density are promising next‐generation battery systems, but the short cycle life and safety concerns caused by the uncontrollable growth of lithium dendrites impede their broad applications. Herein, to address these issues, an ultrarobust composite gel electrolyte (CGE) that can effectively stabilize ion deposition for LMBs is designed via fabricating a specially structured aerogel as the matrix. The gel electrolyte matrix with a 3D interconnected highly porous structures and good affinity with liquid electrolytes is fabricated via compositing bacterial cellulose (BC) and Li_0.33La_0.557TiO₃ nanowires (LLTO NWs) into an aerogel. The composite aerogel matrix demonstrates excellent wettability and liquid electrolyte uptake (586 ± 5%), and the resulting CGE presents exceptional Young's modulus of 1.15 GPa and an extremely high lithium‐ion transference number of 0.88. More significantly, the synergistic effect from the robust BC skeleton and LLTO NWs enabling stable ion deposition effectively suppresses the growth of lithium dendrites. Armed with the CGE, ultrastable symmetric Li/Li cells demonstrate a long cycle life of 1200 h and highly stable performance even at a high current density of 5 mA cm^?2. Furthermore, half cells with the CGE exhibit remarkable enhancement in capacity, cycling stability, and rate performance.     

Unlocking the Potential of Lithium Metal Batteries With a Sulfite-Based Electrolyte

Lithium metal batteries (LMBs) have the potential to significantly increase the energy density of advanced batteries in the future. Nonetheless, the dendritic lithium structures and low Coulombic efficiency (CE) of LMBs currently impede their applied implementation. Herein, a sulfite-based electrolyte (SBE/FEC), including 1.0 m lithium bis(fluorosulfonyl)imide in a blend of ethylene sulfite and diethyl sulfite, and 5 wt% fluoroethylene carbonate is proposed. SBE/FEC is a highly efficient inhibitor against the growth of lithium dendrites through the formation of robust solid electrolyte interphase (SEI) layer. Raman spectroscopy and theoretical calculation indicate that in SBE/FEC, a significant portion of FSI⁻ exists in associated complexes, playing a vital role in the creation of LiF-rich passivation. Besides, the sulfite solvents decompose and yield polysulfide complexes in the SEI layer. A direct correlation between the proportion of cation–anion complexes and the contact angle between electrolyte and separator is elucidated through molecular dynamics simulations. The SBE/FEC system exhibits high CEs (98.3%) with Li||Cu cells, along with a steady discharge capacity of ≈137 mA h g⁻¹ in Li||LiFePO₄ cell. This study presents an effective approach for enhancing LMBs with sulfite-based electrolytes, which can lead to high-energy-density next-generation rechargeable batteries.     

Constructing a High‐Strength Solid Electrolyte Layer by In Vivo Alloying with Aluminum for an Ultrahigh‐Rate Lithium Metal Anode

The serious safety issues caused by uncontrollable lithium (Li) dendrite growth, especially at high current densities, seriously hamper the rapid charging of Li metal‐based batteries. Here, the construction of Al–Li alloy/LiCl‐based Li anode (ALA/Li anode) is reported by displacement and alloying reaction between an AlCl₃‐ionic liquid and a Li foil. This layer not only has high ion‐conductivity and good electron resistivity but also much improved mechanical strength (776 MPa) as well as good flexibility compared to a common solid electrolyte interphase layer (585 MPa). The high mechanical strength of the Al–Li alloy interlayer effectively eliminates volume expansion and dendrite growth in Li metal batteries, so that the ALA/Li anode achieves superior cycling for 1600 h (2.0 mA cm^?2) and 1000 cycles at an ultrahigh current density (20 mA cm^?2) without dendrite formation in symmetric batteries. In lithium–sulfur batteries, the dense alloy layer prevents direct contact between polysulfides and Li metal, inhibiting the shuttle effect and electrolyte decomposition. Long cycling performance is achieved even at a high current density (4 C) and a low electrolyte/sulfur (6.0 µL mg^?1). This easy fabrication process provides a strategy to realize reliable safety during the rapid charging of Li‐metal batteries.     

Effect of the Anion Activity on the Stability of Li Metal Anodes in Lithium‐Sulfur Batteries

With the significant progress made in the development of cathodes in lithium‐sulfur (Li‐S) batteries, the stability of Li metal anodes becomes a more urgent challenge in these batteries. Here the systematic investigation of the stability of the anode/electrolyte interface in Li‐S batteries with concentrated electrolytes containing various lithium salts is reported. It is found that Li‐S batteries using LiTFSI‐based electrolytes are more stable than those using LiFSI‐based electrolytes. The decreased stability is because the N–S bond in the FSI^? anion is fairly weak and the scission of this bond leads to the formation of lithium sulfate (LiSO_x) in the presence of polysulfide species. In contrast, in the LiTFSI‐based electrolyte, the lithium metal anode tends to react with polysulfide to form lithium sulfide (LiS_x), which is more reversible than LiSO_x formed in the LiFSI‐based electrolyte. This fundamental difference in the bond strength of the salt anions in the presence of polysulfide species leads to a large difference in the stability of the anode‐electrolyte interface and performance of the Li‐S batteries with electrolytes composed of these salts. Therefore, anion selection is one of the key parameters in the search for new electrolytes for stable operation of Li‐S batteries.     

Fast Li+ Transport via Silica Network-Driven Nanochannels in Ionomer-in-Framework for Lithium Metal Batteries

For the development of all-solid-state lithium metal batteries (LMBs), a high-porous silica aerogel (SA)-reinforced single-Li⁺ conducting nanocomposite polymer electrolyte (NPE) is prepared via two-step selective functionalization. The mesoporous SA is introduced as a mechanical framework for NPE as well as a channel for fast lithium cation migration. Two types of monomers containing weak-binding imide anions and Li⁺ cations are synthesized and used to prepare NPEs, where these monomers are grafted in SA to produce SA-based NPEs (SANPEs) as ionomer-in-framework. This hybrid SANPE exhibits high ionic conductivities (≈10⁻³ S cm⁻¹), high modulus (≈10⁵ Pa), high lithium transference number (0.84), and wide electrochemical window (>4.8 V). The resultant SANPE in the lithium symmetric cell possesses long-term cyclic stability without short-circuiting over 800 h under 0.2 mA cm⁻². Furthermore, the LiFePO₄|SANPE|Li solid-state batteries present a high discharge capacity of 167 mAh g⁻¹ at 0.1 C, good rate capability up to 1 C, wide operating temperatures (from −10 to 40 °C), and a stable cycling performance with 97% capacity retention and 100% coulombic efficiency after 75 cycles at 1 C and 25 °C. The SANPE demonstrates a new design principle for solid-state electrolytes, allowing for a perfect complex between inorganic silica and organic polymer, for high-energy-density LMBs.     

Non-Flammable Electrolyte with Lithium Nitrate as the Only Lithium Salt for Boosting Ultra-Stable Cycling and Fire-Safety Lithium Metal Batteries

Lithium metal batteries (LMBs) attract considerable attention for their incomparable energy density. However, safety issues caused by uncontrollable lithium dendrites and highly flammable electrolyte limit large-scale LMBs applications. Herein, a low-cost, thermally stable, and low environmentally-sensitive lithium nitrate (LiNO₃) is proposed as the only lithium salt to incorporate with nonflammable triethyl phosphate and fluoroethylene carbonate (FEC) co-solvent as the electrolyte anticipated to enhance the performance of LMBs. Benefiting from the presence of NO₃⁻ and FEC with strong solvation effect and easily reduced ability, a Li₃N–LiF-rich stable solid electrolyte interphase is constructed. Compared to commercial electrolytes, the proposed electrolyte has a high Coulombic efficiency of 98.31% in Li-Cu test at 1 mA cm⁻² of 1.0 mAh cm⁻² with dendrite-free morphology. Additionally, the electrolyte system shows high voltage stability and cathode electrolyte interphase film-forming properties with stable cycling performances, which exhibit outstanding capacity retention rates of 96.39% and 83.74% after 1000 cycles for LFP//Li and NCM811//Li, respectively. Importantly, the non-flammable electrolyte delays the onset of combustion in lithium metal soft pack batteries by 255 s and reduces the peak heat release by 21.02% under the continuous external high-temperature heating condition. The novel electrolyte can contribute immensely to developing high-electrochemical-performance and high-safety LMBs.     

Hydrofluoric Acid-Removable Additive Optimizing Electrode Electrolyte Interphases with Li+ Conductive Moieties for 4.5 V Lithium Metal Batteries

High-voltage lithium metal batteries (LMBs) are capable to achieve the increasing energy density. However, their cycling life is seriously affected by unstable electrolyte/electrode interfaces and capacity instability at high voltage. Herein, a hydrofluoric acid (HF)-removable additive is proposed to optimize electrode electrolyte interphases for addressing the above issues. N, N-dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) aniline (DMPATMB) is used as the electrolyte additive to induce PF₆⁻ decomposition to form a dense and robust LiF-rich solid electrolyte interphase (SEI) for suppressing Li dendrite growth. Moreover, DMPATMB can help to form highly Li⁺ conductive Li₃N and LiBO₂, which can boost the Li⁺ transport across SEI and cathode electrolyte interphase (CEI). In addition, DMPATMB can scavenge traced HF in the electrolyte to protect both SEI and CEI from the corrosion. As expected, 4.5 V Li|| LiNi_0.6Co_0.2Mn_0.2O₂ batteries with such electrolyte deliver 145 mAh g⁻¹ after 140 cycles at 200 mA g⁻¹. This work provides a novel insight into high-voltage electrolyte additives for LMBs.     

An Intrinsically Nonflammable Electrolyte for Prominent-Safety Lithium Metal Batteries with High Energy Density and Cycling Stability

Nex-generation high-energy-density storage battery, assembled with lithium (Li)-metal anode and nickel-rich cathode, puts forward urgent demand for advanced electrolytes that simultaneously possess high security, wide electrochemical window, and good compatibility with electrode materials. Herein an intrinsically nonflammable electrolyte is designed by using 1 M lithium difluoro(oxalato)borate (LiDFOB) in triethyl phosphate (TEP) and N-methyl-N-propyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide [Pyr₁₃][TFSI] ionic liquid (IL) solvents. The introduction of IL can bring plentiful organic cations and anions, which provides a cation shielding effect and regulates the Li⁺ solvation structure with plentiful Li⁺-DFOB⁻ and Li⁺-TFSI⁻ complexes. The unique Li⁺ solvation structure can induce stable anion-derived electrolyte/electrode interphases, which effectively inhibit Li dendrite growth and suppress side reactions between TEP and electrodes. Therefore, the LiNi_0.9Co_0.05Mn_0.05O₂ (NCM90)/Li coin cell with this electrolyte can deliver stable cycling even under 4.5 V and 60 °C. Moreover, a Li-metal battery with thick NCM90 cathode (≈ 15 mg cm⁻²) and thin Li-metal anode (≈ 50 µm) (N/P ≈ 3), also reveals stable cycling performance under 4.4 V. And a 2.2 Ah NCM90/Li pouch cell can simultaneously possess prominent safety with stably passing the nail penetration test, and high gravimetric energy density of 470 Wh kg⁻¹ at 4.4 V.     

Optimizing Main Materials for a Lithium‐Air Battery of High Cycle Life

By optimizing the main materials in lithium‐air batteries, namely sulfolane as electrolyte solvent, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as electrolyte salt, carbon paper as current collector, and Li₂O₂–C hybrids as positive electrode materials, a performance of 800 cycles with a specific capacity of 1000 mAh g^?1 (based on the total mass of positive electrode materials) and an average energy efficiency of 74.72% has been achieved in this work and for the first time reported in the field of lithium‐air battery. Sulfolane‐based electrolyte and carbon paper current collector play the most critical role in building such a lithium‐air battery of high cycle life. The findings described here are expected to benefit the pursuit of green, sustainable, and high‐performance lithium‐air batteries.     

Fluorobenzene,A Low-Density,Economical, and Bifunctional Hydrocarbon Cosolvent for Practical Lithium Metal Batteries

Highly concentrated electrolytes (HCEs) significantly improve the stability of lithium metal anodes, but applications are often impeded by their limitation of density, viscosity, and cost. Here, fluorobenzene (FB), an economical hydrocarbon with low density and low viscosity, is demonstrated as a bifunctional cosolvent to obtain a novel FB diluted highly concentrated electrolyte (FB-DHCE). First, the addition of FB suppresses the decomposition of dimethoxyethane (DME) on the Li metal by strengthening the interactions of DME and FSI⁻ around Li⁺. Second, FB efficiently elevates the content of LiF in the solid electrolyte interphase (SEI) based on its electrochemical reduction reaction. The unique solvation and interfacial chemistry of FB-DHCE enable dendrite-free deposition of lithium with high Coulombic efficiency (up to 99.3%) and prolong cycling life (over 500 cycles at 1 mA cm⁻²). The performance of FB-DHCE is further demonstrated in full cells under practical conditions, including ambient to low temperature (–20 °C), high areal capacity (7.6 mAh cm⁻²), high current density (3 mA cm⁻²), limited excess Li (20 µm Li), and lean electrolyte (3 g Ah⁻¹). Employing FB as a cosolvent not only opens a novel pathway to stabilize Li metal anodes, but also could greatly advance the development of Li metal batteries.