Tape-Casting Li0.34La0.56TiO3 Ceramic Electrolyte Films Permit High Energy Density of Lithium-Metal Batteries

Ceramic oxide electrolytes are outstanding due to their excellent thermostability, wide electrochemical stable windows, superior Li-ion conductivity, and high elastic modulus compared to other electrolytes. To achieve high energy density, all-solid-state batteries require thin solid-state electrolytes that are dozens of micrometers thick due to the high density of ceramic electrolytes. Perovskite-type Li_0.34La_0.56TiO₃ (LLTO) freestanding ceramic electrolyte film with a thickness of 25 µm is prepared by tape-casting. Compared to a thick electrolyte (>200 µm) obtained by cold-pressing, the total Li ionic conductivity of this LLTO film improves from 9.6 × 10⁻⁶ to 2.0 × 10⁻⁵ S cm⁻¹. In addition, the LLTO film with a thickness of 25 µm exhibits a flexural strength of 264 MPa. An all-solid-state Li-metal battery assembled with a 41 µm thick LLTO exhibits an initial discharge capacity of 145 mAh g⁻¹ and a high capacity retention ratio of 86.2% after 50 cycles. Reducing the thickness of oxide ceramic electrolytes is crucial to reduce the resistance of electrolytes and improve the energy density of Li-metal batteries.     

Improved Cycling of Li||NMC811 Batteries under Practical Conditions by a Localized High-Concentration Electrolyte

Li||NMC811 battery, with lithium-metal (high specific capacity and low redox potential) as anode and LiNi_0.8Co_0.1Mn_0.1O₂ (NMC811) as cathode, has been widely accepted to be a good candidate as one of the high-energy-density batteries. However, its cyclability needs improvement to fulfill the requirement for its future commercial use, especially under practical conditions. Electrolyte plays a key role in improving the cycling performance of Li||NMC811 batteries, where a high voltage/electrochemical window and good stability with the electrodes of the electrolyte are required. Herein, a localized high-concentration electrolyte with an additive of lithium difluoro(oxalate)borate (LiDFOB) is reported that improves the cycling performance of Li||NMC811 cells under crucial conditions with Li foil thickness of 50 µm, cathode areal loading of 4 mAh cm⁻², the areal capacity ratio between the negative and positive electrodes (N/P ratio) of 2.6 and the electrolyte/cell capacity ratio (E/C ratio) of 3.0 g (Ah)⁻¹. These cells can maintain 80% of the capacity after 195 cycles.     

New High Donor Electrolyte for Lithium–Sulfur Batteries

The unparalleled theoretical specific energy of lithium–sulfur (Li–S) batteries has attracted considerable research interest from within the battery community. However, most of the long cycling results attained thus far relies on using a large amount of electrolyte in the cell, which adversely affects the specific energy of Li–S batteries. This shortcoming originates from the low solubility of polysulfides in the electrolyte. Here, 1,3-dimethyl-2-imidazolidinone (DMI) is reported as a new high donor electrolyte for Li–S batteries. The high solubility of polysulfides in DMI and its activation of a new reaction route, which engages the sulfur radical (S₃^•−), enables the efficient utilization of sulfur as reflected in the specific capacity of 1595 mAh g⁻¹ under lean electrolyte conditions of 5 μL_electrolyte mg_sulfur⁻¹. Moreover, the addition of LiNO₃ stabilizes the lithium metal interface, thereby elevating the cycling performance to one of the highest known for high donor electrolytes in Li–S cells. These engineered high donor electrolytes are expected to advance Li–S batteries to cover a wide range of practical applications, particularly by incorporating established strategies to realize the reversibility of lithium metal electrodes.     

Achieving Stable Lithium Metal Anode at 50 mA cm−2 Current Density by LiCl Enriched SEI

Lithium metal batteries are intensively studied due to the potential to bring up breakthroughs in high energy density devices. However, the inevitable growth of dendrites will cause the rapid failure of battery especially under high current density. Herein, the utilization of tetrachloroethylene (C₂Cl₄) is reported as the electrolyte additive to induce the formation of the LiCl-rich solid electrolyte interphase (SEI). Because of the lower Li ion diffusion barrier of LiCl, such SEI layer can supply sufficient pathway for rapid Li ion transport, alleviate the concentration polarization at the interface and inhibit the growth of Li dendrites. Meanwhile, the C₂Cl₄ can be continuously replenished during the cycle to ensure the stability of the SEI layer. With the aid of C₂Cl₄-based electrolyte, the Li metal electrodes can maintain stable for >300 h under high current density of 50 mA cm⁻² with areal capacity of 5 mAh cm⁻², broadening the compatibility of lithium metal anode toward practical application scenarios.     

A Single-Ion Conducting Borate Network Polymer as a Viable Quasi-Solid Electrolyte for Lithium Metal Batteries

Lithium-ion batteries have remained a state-of-the-art electrochemical energy storage technology for decades now, but their energy densities are limited by electrode materials and conventional liquid electrolytes can pose significant safety concerns. Lithium metal batteries featuring Li metal anodes, solid polymer electrolytes, and high-voltage cathodes represent promising candidates for next-generation devices exhibiting improved power and safety, but such solid polymer electrolytes generally do not exhibit the required excellent electrochemical properties and thermal stability in tandem. Here, an interpenetrating network polymer with weakly coordinating anion nodes that functions as a high-performing single-ion conducting electrolyte in the presence of minimal plasticizer, with a wide electrochemical stability window, a high room-temperature conductivity of 1.5 × 10⁻⁴ S cm⁻¹, and exceptional selectivity for Li-ion conduction (t_Li+ = 0.95) is reported. Importantly, this material is also flame retardant and highly stable in contact with lithium metal. Significantly, a lithium metal battery prototype containing this quasi-solid electrolyte is shown to outperform a conventional battery featuring a polymer electrolyte.     

Shielding Polysulfide Intermediates by an Organosulfur-Containing Solid Electrolyte Interphase on the Lithium Anode in Lithium–Sulfur Batteries

The lithium–sulfur (Li–S) battery is regarded as a promising high-energy-density battery system, in which the dissolution–precipitation redox reactions of the S cathode are critical. However, soluble Li polysulfides (LiPSs), as the indispensable intermediates, easily diffuse to the Li anode and react with the Li metal severely, thus depleting the active materials and inducing the rapid failure of the battery, especially under practical conditions. Herein, an organosulfur-containing solid electrolyte interphase (SEI) is tailored for the stabilizaiton of the Li anode in Li–S batteries by employing 3,5-bis(trifluoromethyl)thiophenol as an electrolyte additive. The organosulfur-containing SEI protects the Li anode from the detrimental reactions with LiPSs and decreases its corrosion. Under practical conditions with a high-loading S cathode (4.5 mg_S cm⁻²), a low electrolyte/S ratio (5.0 µL mg_S⁻¹), and an ultrathin Li anode (50 µm), a Li–S battery delivers 82 cycles with an organosulfur-containing SEI in comparison to 42 cycles with a routine SEI. This work provokes the vital insights into the role of the organic components of SEI in the protection of the Li anode in practical Li–S batteries.     

High Capacity Li2S–Li2O–LiI Positive Electrodes with Nanoscale Ion-Conduction Pathways for All-Solid-State Li/S Batteries

All-solid-state lithium–sulfur (Li/S) batteries are promising next-generation energy-storage devices owing to their high capacities and long cycle lives. The Li₂S active material used in the positive electrode has a high theoretical capacity; consequently, nanocomposites composed of Li₂S, solid electrolytes, and conductive carbon can be used to fabricate high-energy-density batteries. Moreover, the active material should be constructed with both micro- and nanoscale ion-conduction pathways to ensure high power. Herein, a Li₂S–Li₂O–LiI positive electrode is developed in which the active material is dispersed in an amorphous matrix. Li₂S–Li₂O–LiI exhibits high charge–discharge capacities and a high specific capacity of 998 mAh g⁻¹ at a 2 C rate and 25 °C. X-ray photoelectron spectroscopy, X-ray diffractometry, and transmission electron microscopy observation suggest that Li₂O–LiI provides nanoscale ion-conduction pathways during cycling that activate Li₂S and deliver large capacities; it also exhibits an appropriate onset oxidation voltage for high capacity. Furthermore, a cell with a high areal capacity of 10.6 mAh cm^–2 is demonstrated to successfully operate at 25 °C using a Li₂S–Li₂O–LiI positive electrode. This study represents a major step toward the commercialization of all-solid-state Li/S batteries.     

Tuning the Anode–Electrolyte Interface Chemistry for Garnet-Based Solid-State Li Metal Batteries

Lithium (Li) metal is a promising candidate as the anode for high-energy-density solid-state batteries. However, interface issues, including large interfacial resistance and the generation of Li dendrites, have always frustrated the attempt to commercialize solid-state Li metal batteries (SSLBs). Here, it is reported that infusing garnet-type solid electrolytes (GSEs) with the air-stable electrolyte Li₃PO₄ (LPO) dramatically reduces the interfacial resistance to ≈1 Ω cm² and achieves a high critical current density of 2.2 mA cm⁻² under ambient conditions due to the enhanced interfacial stability to the Li metal anode. The coated and infused LPO electrolytes not only improve the mechanical strength and Li-ion conductivity of the grain boundaries, but also form a stable Li-ion conductive but electron-insulating LPO-derived solid-electrolyte interphase between the Li metal and the GSE. Consequently, the growth of Li dendrites is eliminated and the direct reduction of the GSE by Li metal over a long cycle life is prevented. This interface engineering approach together with grain-boundary modification on GSEs represents a promising strategy to revolutionize the anode–electrolyte interface chemistry for SSLBs and provides a new design strategy for other types of solid-state batteries.     

High Areal Capacity,Long Cycle Life Li–Air Batteries Enabled by Nano/Micro Hierarchical Porous Cathode

The limited cycle life of Li–air batteries (LABs) with high areal capacity remains the chief challenge that hinders their practical applications. Here, the study proposes a hierarchical porous electrode (HPE) design strategy, in which porous MnO nanoflowers are built into mesopore/macropore electrodes through a combination of chemical dealloying and physical de-templating procedures. The MnO nanoflowers with 10–30 nm pore provides active sites to catalyze the O₂ reduction and decomposition of discharged products. The 5–10 µm macroscopic pores in the cathode serve as channels of O₂ transportation and facilitate the electrolyte permeation. The proposed HPE exhibits a full discharge capacity of 17.49 mAh cm⁻² and stable cycle life >2000 h with a limited capacity of 6 mAh cm⁻². These results suggest that the HPE design strategy for LABs can simultaneously provide large capacity and robust cycle life, which is promising for advanced metal–air batteries.     

Weak-Coordination Electrolyte Enabling Fast Li+ Transport in Lithium Metal Batteries at Ultra-Low Temperature

Lithium metal batteries (LMBs) are promising for next-generation high-energy-density batteries owing to the highest specific capacity and the lowest potential of Li metal anode. However, the LMBs are normally confronted with drastic capacity fading under extremely cold conditions mainly due to the freezing issue and sluggish Li⁺ desolvation process in commercial ethylene carbonate (EC)-based electrolyte at ultra-low temperature (e.g., below −30 °C). To overcome the above challenges, an anti-freezing carboxylic ester of methyl propionate (MP)-based electrolyte with weak Li⁺ coordination and low-freezing temperature (below −60 °C) is designed, and the corresponding LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) cathode exhibits a higher discharge capacity of 84.2 mAh g⁻¹ and energy density of 195.0 Wh kg⁻¹_cathode than that of the cathode (1.6 mAh g⁻¹ and 3.9 Wh kg⁻¹_cathode) working in commercial EC-based electrolytes for NCM811‖ Li cell at −60 °C. Molecular dynamics simulation, Raman spectra, and nuclear magnetic resonance characterizations reveal that rich mobile Li⁺ and the unique solvation structure with weak Li⁺ coordination are achieved in MP-based electrolyte, which collectively facilitate the Li⁺ transference process at low temperature. This work provides fundamental insights into low-temperature electrolytes by regulating solvation structure, and offers the basic guidelines for the design of low-temperature electrolytes for LMBs.     

Composite Solid Electrolyte with Continuous and Fast Organic–Inorganic Ion Transport Highways Created by 3D Crimped Nanofibers@functional Ceramic Nanowires

A 3D crimped sulfonated polyethersulfone-polyethylene oxide(C-SPES/PEO) nanofiber membrane and long-range lanthanum cobaltate(LaCoO₃) nanowires are collectively doped into a PEO matrix to acquire a composite solid electrolyte (C-SPES-PEO-LaCoO₃) for all-solid-state lithium metal batteries(ASSLMBs). The 3D crimped structure enables the fiber membrane to have a large porosity of 90%. Therefore, under the premise of strongly guaranteeing the mechanical properties of C-SPES-PEO-LaCoO₃, the ceramic nanowires conveniently penetrated into the 3D crimped SPES nanofiber without being blocked, which can facilitate fast ionic conductivity by forming 3D continuous organic–inorganic ion transport pathways. The as-prepared electrolyte delivers an excellent ionic conductivity of 2.5 × 10⁻⁴ S cm⁻¹ at 30 °C. Density functional theory calculations indicate that the LaCoO₃ nanowires and 3D crimped C-SPES/PEO fibers contribute to Li⁺ movement. Particularly, the LiFePO₄/C-SPES-PEO-LaCoO₃ /Li and NMC811/C-SPES-PEO-LaCoO₃/Li pouch cell have a high initial discharge specific capacity of 156.8 mAh g⁻¹ and a maximum value of 176.7 mAh g⁻¹, respectively. In addition, the universality of the penetration of C-SPES/PEO nanofibers to functional ceramic nanowires is also reflected by the stable cycling performance of ASSLMBs based on the electrolytes, in which the LaCoO₃ nanowires are replaced with Gd-doped CeO₂ nanowires. The work will provide a novel approach to high performance solid-state electrolytes.     

Stable bismuth-antimony alloy cathode with a conversion-dissolution/deposition mechanism for high-performance zinc batteries

Although a large number of intercalation cathode materials for aqueous Zn batteries have been reported, limited intercalation capacity precludes achieving a higher energy density. Here we develop a high-performance aqueous Zn battery based on BiSb alloy (Bi_0.5Sb_0.5) using a high-concentrated strong-basic polyelectrolyte. We demonstrate that a conversion-dissolution/deposition electrochemical mechanism (BiSb ↔ Bi + SbO₂⁻ ↔ Bi + SbO₃⁻ ↔ Bi₂O₃) through in situ X-ray diffraction (XRD), Raman, and ex-situ X-ray photoelectron spectrometry (XPS) characterizations with the help of density functional theory calculations. The BiSb cathode delivers large capacity of 512 mAh g⁻¹ at 0.3 Ag⁻¹ and superior rate capability of 90 mAh g⁻¹ even at 20 Ag⁻¹, and long-term cyclability with capacity retentions of 184 mAh g⁻¹ after 600 cycles at 0.5 Ag⁻¹ and 130 mAh g⁻¹ after 1300 cycles at 1 Ag⁻¹. Remarkably, even at temperatures as low as −10 and −20 °C, capacities of 210 and 197 mAh g⁻¹ are reserved at 1 Ag⁻¹, respectively. Moreover, the prepared pouch Zn//BiSb battery delivers a high energy density of 303 Wh kg⁻¹_BiSb at 0.3 Ag⁻¹. When coupled with a high concentration polyelectrolyte, the Zn/BiSb battery exhibits an excellent performance over a wide temperature range (−40 to 40 °C). Our research reveals the metal cathode is promising for Zn batteries to achieve a high performance with the unique mechanism and alloys can be an effective approach to stabilize metal electrodes for cycling.     

An Electron/Ion Dual‐Conductive Alloy Framework for High‐Rate and High‐Capacity Solid‐State Lithium‐Metal Batteries

The solid‐state Li battery is a promising energy‐storage system that is both safe and features a high energy density. A main obstacle to its application is the poor interface contact between the solid electrodes and the ceramic electrolyte. Surface treatment methods have been proposed to improve the interface of the ceramic electrolytes, but they are generally limited to low‐capacity or short‐term cycling. Herein, an electron/ion dual‐conductive solid framework is proposed by partially dealloying the Li–Mg alloy anode on a garnet‐type solid‐state electrolyte. The Li–Mg alloy framework serves as a solid electron/ion dual‐conductive Li host during cell cycling, in which the Li metal can cycle as a Li‐rich or Li‐deficient alloy anode, free from interface deterioration or volume collapse. Thus, the capacity, current density, and cycle life of the solid Li anode are improved. The cycle capability of this solid anode is demonstrated by cycling for 500 h at 1 mA cm^?2, followed by another 500 h at 2 mA cm^?2 without short‐circuiting, realizing a record high cumulative capacity of 750 mA h cm^?2 for garnet‐type all‐solid‐state Li batteries. This alloy framework with electron/ion dual‐conductive pathways creates the possibility to realize high‐energy solid‐state Li batteries with extended lifespans.     

Anchoring and Catalytic Effects of rGO Supported VS2 Nanosheets Enable High-Performance Li–Organosulfur Battery

As a high-energy-density cathode material, organosulfur has great potential for lithium batteries. However, their practical application is plagued by electronic/ionic insulation and sluggish redox kinetics. Hence, our strategy is to design a self-weaving, freestanding host material by introducing reduced graphene oxide–supported VS₂ nanosheets (VS₂-rGO) and carbon nanotubes (CNTs) for lithium–phenyl tetrasulfide (Li–PTS) batteries. Unique host materials not only provide physicochemical confinement of active materials to boost the utilization but also catalyze the conversion of active materials to accelerate redox kinetics. Therefore, Li–PTS cell based on the 3D VS₂-rGO-CNTs (VSGC) host material shows excellent cyclability, with a slow capacity decay rate of 0.08% per cycle over 500 cycles at 0.5 C, and a high areal capacity of 3.1 mAh cm⁻² with the PTS loading of 7.2 mg cm⁻². More importantly, the potential for practical applications is highlighted by the flexible pouch cell with a high areal capacity (4.1 mAh cm⁻²) and a low electrolyte/PTS ratio (3.5 µL mg⁻¹). This work sheds light on elevating the electrochemical performance of Li–organosulfur batteries through the effective catalytic and adsorbed host material.     

Long-Cycling-Life Sodium-Ion Battery Using Binary Metal Sulfide Hybrid Nanocages as Anode

Due to the relatively high capacity and lower cost, transition metal sulfides (TMS) as anode show promising potential in sodium-ion batteries (SIBs). Herein, a binary metal sulfide hybrid consisting of carbon encapsulated CoS/Cu₂S nanocages (CoS/Cu₂S@C-NC) is constructed. The interlocked hetero-architecture filled with conductive carbon accelerates the Na⁺/e⁻ transfer, thus leading to improved electrochemical kinetics. Also the protective carbon layer can provide better volume accommondation upon charging/discharging. As a result, the battery with CoS/Cu₂S@C-NC as anode displays a high capacity of 435.3 mAh g⁻¹ after 1000 cycles at 2.0 A g⁻¹ (≈3.4 C). Under a higher rate of 10.0 A g⁻¹ (≈17 C), a capacity of as high as 347.2 mAh g⁻¹ is still remained after long 2300 cycles. The capacity decay per cycle is only 0.017%. The battery also exhibits a better temperature tolerance at 50 and −5 °C. A low internal impedance analyzed by X-ray diffraction patterns and galvanostatic intermittent titration technique, narrow band gap, and high density of states obtained by first-principle calculations of the binary sulfides, ensure the rapid Na⁺/e⁻ transport. The long-cycling-life SIB using binary metal sulfide hybrid nanocages as anode shows promising applications in versatile electronic devices.     

Borohydride‐Scaffolded Li/Na/Mg Fast Ionic Conductors for Promising Solid‐State Electrolytes

Borohydride solid‐state electrolytes with room‐temperature ionic conductivity up to ≈70 mS cm^?1 have achieved impressive progress and quickly taken their place among the superionic conductive solid‐state electrolytes. Here, the focus is on state‐of‐the‐art developments in borohydride solid‐state electrolytes, including their competitive ionic‐conductive performance, current limitations for practical applications in solid‐state batteries, and the strategies to address their problems. To open, fast Li/Na/Mg ionic conductivity in electrolytes with BH₄ ^? groups, approaches to engineering borohydrides with enhanced ionic conductivity, and later on the superionic conductivity of polyhedral borohydrides, their correlated conductive kinetics/thermodynamics, and the theoretically predicted high conductive derivatives are discussed. Furthermore, the validity of borohydride pairing with coated oxides, sulfur, organic electrodes, MgH₂, TiS₂, Li₄Ti₅O₁₂, electrode materials, etc., is surveyed in solid‐state batteries. From the viewpoint of compatible cathodes, the stable electrochemical windows of borohydride solid‐state electrolytes, the electrode/electrolyte interface behavior and battery device design, and the performance optimization of borohydride‐based solid‐state batteries are also discussed in detail. A comprehensive coverage of emerging trends in borohydride solid‐state electrolytes is provided and future maps to promote better performance of borohydride SSEs are sketched out, which will pave the way for their further development in the field of energy storage.     

Lithiophilic Magnetic Host Facilitates Target-Deposited Lithium for Practical Lithium-Metal Batteries

Lithium-metal shows promising prospects in constructing various high-energy-density lithium-metal batteries (LMBs) while long-lasting tricky issues including the uncontrolled dendritic lithium growth and infinite lithium volume expansion seriously impede the application of LMBs. In this work, it is originally found that a unique lithiophilic magnetic host matrix (Co₃O₄-CCNFs) can simultaneously eliminate the uncontrolled dendritic lithium growth and huge lithium volume expansion that commonly occur in typical LMBs. The magnetic Co₃O₄ nanocrystals which inherently embed on the host matrix act as nucleation sites and can also induce micromagnetic field and facilitate a targeted and ordered lithium deposition behavior thus, eliminating the formation of dendritic Li. Meanwhile, the conductive host can effectively homogenize the current distribution and Li-ion flux, thus, further relieving the volume expansion during cycling. Benefiting from this, the featured electrodes demonstrate ultra-high coulombic efficiency of 99.1% under 1 mA cm⁻² and 1 mAh cm⁻². Symmetric cell under limited Li (10 mAh cm⁻²) inspiringly delivers ultralong cycle life of 1600 h (under 2 mA cm⁻², 1 mAh cm⁻²). Moreover, LiFePO₄||Co₃O₄-CCNFs@Li full-cell under practical condition of limited negative/positive capacity ratio (2.3:1) can deliver remarkably improved cycling stability (with 86.6% capacity retention over 440 cycles).     

The Interaction in Electrolyte Additives Accelerates Ion Transport to Achieve High-Energy Non-Aqueous Lithium Metal Batteries

Electrolyte engineering is a feasible strategy to realize high energy density lithium metal batteries. However, stabilizing both lithium metal anodes and nickel-rich layered cathodes is extremely challenging. To break through this bottleneck, a dual-additives electrolyte containing fluoroethylene carbonate (10 vol.%) and 1-methoxy-2-propylamine (1 vol.%) in conventional LiPF₆-containing carbonate-based electrolyte is reported. The two additives can polymerize and thus generate dense and uniform LiF and Li₃N-containing interphases on both electrodes’ surfaces. Such robust ionic conductive interphases not only prevent lithium dendrite formation in lithium metal anode but also suppress stress-corrosion cracking and phase transformation in nickel-rich layered cathode. The advanced electrolyte enables Li||LiNi_0.8Co_0.1Mn_0.1O₂ stably cycle for 80 cycles at 60 mA g⁻¹ with a specific discharge capacity retention of 91.2% under harsh conditions.     

Regulating Li-Ion Transport through Ultrathin Molecular Membrane to Enable High-Performance All-Solid-State–Battery

Solid-state lithium metal batteries with garnet-type electrolyte provide several advantages over conventional lithium-ion batteries, especially for safety and energy density. However, a few grand challenges such as the propagation of Li dendrites, poor interfacial contact between the solid electrolyte and the electrodes, and formation of lithium carbonate during ambient exposure over the solid-state electrolyte prevent the viability of such batteries. Herein, an ultrathin sub-nanometer porous carbon nanomembrane (CNM) is employed on the surface of solid-state electrolyte (SSE) that increases the adhesion of SSE with electrodes, prevents lithium carbonate formation over the surface, regulates the flow of Li-ions, and blocks any electronic leakage. The sub-nanometer scale pores in CNM allow rapid permeation of Li-ions across the electrode–electrolyte interface without the presence of any liquid medium. Additionally, CNM suppresses the propagation of Li dendrites by over sevenfold up to a current density of 0.7 mA cm⁻² and enables the cycling of all-solid-state batteries at low stack pressure of 2 MPa using LiFePO₄ cathode and Li metal anode. The CNM provides chemical stability to the solid electrolyte for over 4 weeks of ambient exposure with less than a 4% increase in surface impurities.     

Thiol-Branched Solid Polymer Electrolyte Featuring High Strength,Toughness, and Lithium Ionic Conductivity for Lithium-Metal Batteries

Lithium-metal batteries (LMBs) with high energy densities are highly desirable for energy storage, but generally suffer from dendrite growth and side reactions in liquid electrolytes; thus the need for solid electrolytes with high mechanical strength, ionic conductivity, and compatible interface arises. Herein, a thiol-branched solid polymer electrolyte (SPE) is introduced featuring high Li⁺ conductivity (2.26 × 10⁻⁴ S cm⁻¹ at room temperature) and good mechanical strength (9.4 MPa)/toughness (≈500%), thus unblocking the tradeoff between ionic conductivity and mechanical robustness in polymer electrolytes. The SPE (denoted as M-S-PEGDA) is fabricated by covalently cross-linking metal–organic frameworks (MOFs), tetrakis (3-mercaptopropionic acid) pentaerythritol (PETMP), and poly(ethylene glycol) diacrylate (PEGDA) via multiple C S C bonds. The SPE also exhibits a high electrochemical window (>5.4 V), low interfacial impedance (<550 Ω), and impressive Li⁺ transference number (t_Li+ = 0.44). As a result, Li||Li symmetrical cells with the thiol-branched SPE displayed a high stability in a >1300 h cycling test. Moreover, a Li|M-S-PEGDA|LiFePO₄ full cell demonstrates discharge capacity of 143.7 mAh g⁻¹ and maintains 85.6% after 500 cycles at 0.5 C, displaying one of the most outstanding performances for SPEs to date.