Ultra-Thin Single-Particle-Layer Sodium Beta-Alumina-Based Composite Polymer Electrolyte Membrane for Sodium-Metal Batteries

Inorganic/organic composite polymer electrolytes (CPEs) with good flexibility and electrode contact have been pursued for solid−state sodium-metal batteries. However, the application of CPEs for high energy density solid−state sodium-metal batteries is still limited by the low Na⁺ conductivity, large thickness, and low ion transference number. Herein, an ultra-thin single-particle-layer (UTSPL) composite polymer electrolyte membrane with a thickness of ≈20 µm straddled by a sodium beta−alumina ceramic electrolyte (SBACE) is presented. A ceramic Na⁺-ion electrolyte that bridges or percolates across an ultra-thin and flexible polymer membrane provides: 1) the strength and flexibility from the polymer membrane, 2) excellent electrolyte/electrode interfacial contact, and 3) a percolation path for Na⁺-ion transfer. Owing to this novel design, the obtained UTSPL-35SBACE membrane exhibits a high Na⁺-ion conductivity of 0.19 mS cm⁻¹ and a transference number of 0.91 at room temperature, contributing to long−term cycling stability of symmetric sodium cells with a small overpotential. The assembled quasi-solid-state cell with the as−prepared UTSPL-35SBACE membrane displays superior cycling performance with a discharge capacity of 105 mAh g⁻¹ at 0.5 °C rate after 100 cycles and excellent rate performance (82 mAh g⁻¹ at 5 °C rate) at room temperature with the potassium manganese hexacyanoferrate (KMHCF)@CNTs/CNFs cathode, where KMHCF refers to potassium manganese hexacyanoferrate.     

Ultrathin Layered Double Hydroxide Nanosheets Enabling Composite Polymer Electrolyte for All-Solid-State Lithium Batteries at Room Temperature

Solid electrolytes are the most promising substitutes for liquid electrolytes to construct high-safety and high-energy-density energy storage devices. Nevertheless, the poor lithium ion mobility and ionic conductivity at room temperature (RT) have seriously hindered their practical usage. Herein, single-layer layered-double-hydroxide nanosheets (SLN) reinforced poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) composite polymer electrolyte is designed, which delivers an exceptionally high ionic conductivity of 2.2 × 10⁻⁴ S cm⁻¹ (25  ° C), superior Li⁺ transfer number ( ≈ 0.78) and wide electrochemical window ( ≈ 4.9 V) with a low SLN loading ( ≈ 1 wt%). The Li symmetric cells demonstrate ultra-long lifespan stable cycling over ≈ 900 h at 0.1 mA cm⁻², RT. Moreover, the all-solid-state Li|LiFePO₄ cells can run stably with a high capacity retention of 98.6% over 190 cycles at 0.1 C, RT. Moreover, using LiCoO₂/LiNi_0.8Co_0.1Mn_0.1O₂, the all-solid-state lithium metal batteries also demonstrate excellent cycling at RT. Density functional theory calculations are performed to elucidate the working mechanism of SLN in the polymer matrix. This is the first report of all-solid-state lithium batteries working at RT with PVDF-HFP based solid electrolyte, providing a novel strategy and significant step toward cost-effective and scalable solid electrolytes for practical usage at RT.     

Sol Electrolyte: Pathway to Long-Term Stable Lithium Metal Anode

Lithium (Li) metal batteries are the subject of intense study due to their high energy densities. However, uncontrolled dendrite growth and the resulting pulverization of Li foil during the repeated plating/stripping process seriously diminish their cycling life. Herein, a facile approach using octaphenyl polyoxyethylene (OP-10)-based sol electrolyte is proposed to alleviate Li anode pulverization. This sol electrolyte possesses better ionic conductivity compared to gel and solid-state electrolytes and also homogenizes Li ion diffusion throughout the entire electrolyte efficiently. As a result, Li/Li symmetric cells using this sol electrolyte demonstrate long-term cycling stability for up to 1800 h, with a plating capacity of 3.0 mAh cm⁻² without deteriorating the integrity of the thin Li foil. Using a conventional liquid electrolyte, electrode pulverization and battery failure can be observed after just three cycles. More importantly, a parameter of “throwing power” is introduced in a metal Li battery system to characterize the homogenizing ability of Li deposition in different electrolyte systems, which can serve as a guide to the efficient selection of electrolytes for Li metal batteries.     

Quasi-Liquid Gel Electrolyte for Enhanced Flexible Zn–Air Batteries

Flexible Zn–air batteries (FZABs) have attracted more attention due to their high specific energy, excellent stability, and unique rechargeability. However, these batteries are limited by the low conductivity of the gel electrolytes used. Here a quasi-liquid gel with ionic conductivity comparable to liquid electrolytes is presented. The gel pore structure is guided and modified in situ with large-size silica to achieve clear and unbroken pores. The reduced skeleton structure leads to a significant increase in ionic conductivity to 562.6 mS cm⁻¹, enabling a peak power density of 154 mW cm⁻² and a cycle life of over 40 h with a low charge–discharge gap. The FZABs also exhibit a high lifetime and potential advantages in 10 mA cm⁻² charge/discharge testing, and demonstrate excellent performance in practical applications. This study offers new possibilities for developing high-performance quasi-liquid gels and innovative concepts for FZABs.     

A Robust Dual-Polymer@Inorganic Networks Composite Polymer Electrolyte Toward Ultra-Long-Life and High-Voltage Li/Li-Rich Metal Battery

Composite polymer electrolytes (CSEs) that simultaneously possess superior electrochemical performances with robust mechanical properties are highly desired to the application of high-energy lithium metal batteries. Herein, a novel dual-polymer@inorganic network CSE (DNSE@IN) through a sequential nonhydrolytic sol-gel reaction of tetraethoxysilane (TEOS) and the semi-interpenetration of poly(vinylidene fluoride-co-hexafluoropropene)-hexafluoropropylene (P(VDF-HFP)) with poly(ionic liquid) (PIL) is proposed. DNSE@IN, which has a robust dual-polymer@inorganic networks, not only has high ionic conductivity (0.53 mS cm⁻¹ at 20 °C), but also exhibits an outstanding Young's modulus of 723.2 MPa. As a result, the DNSE@IN based Li/LiFePO₄ and Li/Li_1.17Ni_0.27Co_0.05Mn_0.52O₂ (Li-rich) cells exhibit remarkable cycling stability from room temperature (RT) to 100 °C. As-assembled Li/Li-rich battery shows superior cyclability of 194.3 mAh g⁻¹ after 70 cycles at 4.3 V under RT. Additionally, the scale-up high-voltage Li/Li-rich pouch cells exhibit excellent cyclability (nearly 100% capacity retention after 93 cycles) and superior flexibility, safety at RT for potential practical applications. As such, the work of decoupling ionic conductivity and mechanical properties opens a novel route to develop novel CSEs for the construction of high-energy lithium metal batteries.     

Facile Li+ Transport in Interpenetrating O- and F-Containing Polymer Networks for Solid-State Lithium Batteries

Solid polymer electrolytes (SPEs) provide an intimate contact with electrodes and accommodate volume changes in the Li-anode, making them ideal for all-solid-state batteries (ASSBs); however, confined chain swing, poor ion-complex dissociation, and barricaded Li⁺-transport pathways limit the ionic conductivity of SPEs. This study develops an interpenetrating polymer network electrolyte (IPNE) comprising poly(ethylene oxide)- and poly(vinylidene fluoride)-based networked SPEs (O-NSPE and F-NSPE, respectively) and lithium bis(fluorosulfonyl) imide (LiFSI) to address these challenges. The  CF₂ / CF₃ segments of the F-NSPE segregate FSI⁻ to form connected Li⁺-diffusion domains, and  C O C segments of the O-NSPE dissociate the complexed ions to expedite Li⁺ transport. The synergy between O-NSPE and F-NSPE gives IPNE high ionic conductivity (≈1 mS cm⁻¹) and a high Li-transference number (≈0.7) at 30 °C. FSI⁻ aggregation prevents the formation of a space-charge zone on the Li-anode surface to enable uniform Li deposition. In Li||Li cells, the proposed IPNE exhibits an exchange current density exceeding that of liquid electrolytes (LEs). A Li|IPNE|LiFePO₄ ASSB achieves charge–discharge performance superior to that of LE-based batteries and delivers a high rate of 7 mA cm⁻². Exploiting the synergy between polymer networks to construct speedy Li⁺-transport pathways is a promising approach to the further development of SPEs.     

Hierarchical Composite-Solid-Electrolyte with High Electrochemical Stability and Interfacial Regulation for Boosting Ultra-Stable Lithium Batteries

Solid-state electrolytes have drawn enormous attention to reviving lithium batteries but have also been barricaded in lower ionic conductivity at room temperature, awkward interfacial contact, and severe polarization. Herein, a sort of hierarchical composite solid electrolyte combined with a “polymer-in-separator” matrix and “garnet-at-interface” layer is prepared via a facile process. The commercial polyvinylidene fluoride-based separator is applied as a host for the polymer-based ionic conductor, which concurrently inhibits over-polarization of polymer matrix and elevates high-voltage compatibility versus cathode. Attached on the side, the compact garnet (Li_6.4La₃Zr_1.4Ta_0.6O₁₂) layer is glued to physically inhibit the overgrowth of lithium dendrite and regulate the interfacial electrochemistry. At 25 °C, the electrolyte exhibits a high ionic conductivity of 2.73 × 10⁻⁴ S cm⁻¹ and a decent electrochemical window of 4.77 V. Benefiting from this elaborate electrolyte, the symmetrical Li||Li battery achieves steady lithium plating/stripping more than 4800 h at 0.5 mA cm⁻² without dendrites and short-circuit. The solid-state batteries deliver preferable capacity output with outstanding cycling stability (95.2% capacity retained after 500 cycles, 79.0% after 1000 cycles at 1 C) at ambient temperature. This hierarchical structure design of electrolyte may reveal great potentials for future development in fields of solid-state metal batteries.     

Brine Refrigerants for Low-cost,Safe Aqueous Supercapacitors with Ultra-long Stable Operation at Low Temperatures

Traditional aqueous energy storage devices are difficult to operate at low temperatures owing to the poor ionic conductivity and sluggish interfacial dynamics in frozen electrolytes. Herein, the low-cost brine refrigerants for food freezing and preservation as electrolytes, and unexpectedly realize high ionic conductivity and stable operation of an aqueous storage device at low temperatures are demonstrated. A CaCl₂ brine refrigerant electrolyte (BRE) with a low freezing point −55 °C and high ionic conductivity (10.1 mS cm⁻¹ at −50 °C) is developed for supercapacitors (SCs), which retains 80% of the room temperature capacity at −50 °C and exhibits ultra-long cycle life with excellent capacity retention of 92% over 98,500 cycles, outperforming the other SCs which can be operated below −40 °C in literature. Moreover, the SCs with MgCl₂ and NaCl BREs can also be operated successfully with excellent cycle stability and high-capacity retention at low temperatures of −30 and −20 °C, respectively. Fundamental correlation between various cations and their effect on the freezing point reduction of aqueous electrolytes is revealed via Raman investigation and molecular dynamics simulations. This study provides a rational design strategy for green, inexpensive, and safe low-temperature aqueous electrolytes for energy storage devices.     

Antifreezing Zwitterionic Hydrogel Electrolyte with High Conductivity of 12.6 mS cm−1 at −40 °C through Hydrated Lithium Ion Hopping Migration

Hydrogel electrolytes have high room-temperature conductivity and can be widely used in energy storage device. However, hydrogels suffer from the inevitable freezing of water at subzero temperatures, resulting in the diminishment of their conductivity and mechanical properties. How to achieve high conductivity without sacrificing hydrogels’ flexibility at subzero temperature is an important challenge. To address this challenge, a new type of zwitterionic polymer hydrogel (polySH) electrolytes is fabricated. The anionic and cationic counterions on the polymer chains facilitate the dissociation of LiCl. The antifreezing electrolyte can be stretched to a strain of 325% and compressed to 75% at −40 °C and possesses an outstanding conductivity of 12.6 mS cm⁻¹ at −40 °C. A direct hopping migration mechanism of hydrated lithium-ion through the channel of zwitterion groups is proposed. The polySH electrolyte-based-supercapacitor (SC) exhibits a high specific capacitance of 178 mF cm⁻² at 60 °C and 134 mF cm⁻² at −30 °C with a retention of 81% and 71% of the initial capacitance after 10 000 cycles, respectively. The overall merits of the electrolyte will open up a new avenue for advanced ionic conductors and energy storage device in practical applications.     

Regulating Na-ion Solvation in Quasi-Solid Electrolyte to Stabilize Na Metal Anode

Sodium metal batteries are promising for cost-effective energy storage, however, the sluggish ion transport in electrolytes and detrimental sodium-dendrite growth stall their practical applications. Herein, a cross-linking quasi-solid electrolyte with a high ionic conductivity of 1.4 mS cm⁻¹ at 25 °C is developed by in-situ polymerizing poly (ethylene glycol) diacrylate-based monomer. Benefiting from the refined solvation structure of Na⁺ with a much lower desolvation barrier, random Na⁺ diffusion on the Na surface is restrained, so that the Na dendrite formation is suppressed. Consequently, symmetrical Na||Na cells employing the electrolyte can be cycled >2000 h at 0.1 mA cm⁻². Na₃V₂(PO₄)₃||Na batteries reveal a high discharge specific capacity of 66.1 mAh g⁻¹ at 15 C and demonstrate stable cycling over 1000 cycles with a capacity retention of 83% at a fast rate of 5 C.     

Nonpolar Cosolvent Driving LUMO Energy Evolution of Methyl Acetate Electrolyte to Afford Lithium-Ion Batteries Operating at −60 °C

The operation of lithium-ion batteries (LIBs) at low temperatures (<−20 °C) is hindered by the low conductivity and high viscosity of conventional carbonate electrolytes. Methyl acetate (MA) has proven to be a competitive low-temperature electrolyte solvent with low viscosity and low freezing point, but its interfacial stability is poor and remains elusive until now. Here, it is revealed thaat the reductive stability of MA-based electrolytes is fundamentally governed by the anion-prevailed solvation structure. Based on this framework, fluorobenzene is employed in the electrolyte to promote the entry of anions into the solvation shell via dipole-dipole interactions and the generation of free MA, thus enhancing the lowest unoccupied molecular orbital energy of MA. The designed electrolyte enables LiCoO₂ (LCO)/graphite cells to exhibit excellent cycling performance at −20 °C (90% retention after 1000 cycles at 1 C) and to remain 91% of their room-temperature capacity at a super-low temperature of −60 °C at 0.05 C. Thanks to the plentiful free MA, this electrolyte has a high conductivity (2.61 mS cm⁻¹) at −60 °C and allows LCO/graphite cell to charge at −60 °C. This study offers the possibility of practical applications for those solvents with poor reductive stability and provides new approaches to designing advanced electrolytes for low-temperature applications.     

Highly Reversible Zinc-Air Batteries at −40 °C Enabled by Anion-Mediated Biomimetic Fat

The wide application of portable electrical equipment, aerial vehicles, smart robotics, etc. has boosted the development of advanced batteries with safety, high energy density, and environmental adaptability. Inspired by the fat layer on animal bodies, biomimetic fat is constructed as electrolytes of solid-state zinc-air batteries to achieve excellent cycling performance at low temperatures. Via tailored anion-H₂O interaction, the antifreezing gel electrolytes, with the multi-performance of interface compatibility, temperature adaptability, and stable power supply simultaneously, build robust Zn|electrolyte interface, thus promoting uniform interfacial electric fields and Zn deposition. Excellent long-term cyclability of 120 h at a high current density of 50 mA cm⁻² are exhibited at 25 °C. Moreover, at −40 °C, a record-long cycling life of 205 h at a current density as large as 10 mA cm⁻² is achieved.     

A Hetero-Layered,Mechanically Reinforced,Ultra-Lightweight Composite Polymer Electrolyte for Wide-Temperature-Range,Solid-State Sodium Batteries

The practical use of polyethylene oxide polymer electrolyte in the solid-state sodium metallic batteries (SSMBs) suffers from the retard Na⁺ diffusion at the room temperature, mechanical fragility as well as the oxidation tendency at high voltages. Herein, a hetero-layered composite polymeric electrolyte (CPE) is proposed to enable the simultaneous interfacial stability with the high voltage cathodes (till 4.2 V) and Na metallic anode. Being incorporated within the polymer matrix, the sand-milled Na₃Zr₂Si₂PO₁₂ nanofillers and nanocellulose scaffold collectively endow the thin-layer (25 µm), ultralightweight (1.65 mg cm⁻²) CPE formation with an order of magnitude enhancement of the mechanical strength (13.84 MPa) and ionic conductivity (1.62 × 10⁻⁴ S cm⁻¹) as compared to the pristine polymer electrolyte, more importantly, the improved dimension stability up to 180 °C. Upon the integration of the hetero-layered CPE with the iron hexacyanoferrate FeHCF cathode (1 mAh cm⁻²) and the Na foil, the cell model can achieve the room-temperature cycling stability (93.73% capacity retention for 200 cycles) as well as the high temperature tolerance till 80 °C, which inspires a quantum leap toward the surface-wetting-agent-free, energy-dense, wide-temperature-range SSMB prototyping.     

Ultrastretchable Ionogel with Extreme Environmental Resilience through Controlled Hydration Interactions

Ionic conductive gels are widely sought after for applications that require reliable ionic conduction and mechanical performance under extreme conditions, which remains a grand challenge. To address this limitation, water-induced hydration interactions are deliberately controlled within the ionic liquid (IL)-based conductive gels (ionogels) to achieve all-round performance. Specifically, the competitive interactions between IL, water and cellulose nanofibrils (CNF) are balanced to preserve the nanoscale morphology of CNF while avoiding its dissolution. As a result, both mechanical performance and ionic conductivity of the resultant ionogel are synergistically enhanced. For instance, an ultra stretchable ionogel (up to 10250 ± 412% stretchability) with both high toughness (21.8 ± 0.9 MJ m⁻³) and ionic conductivity (0.70 ± 0.06 S m⁻¹) is achieved. Furthermore, multimodal sensing functions (strain, compression, temperature, and humidity) are realized by assembling the ionogel as a skin-like membrane. Due to the low volatility of IL and its strong interaction with water, the ionogel maintains an excellent performance at either ultra-low temperature (−45 °C), high temperature (75 °C) or low humidity environment (RH < 15%), demonstrating superb anti-freezing and anti-drying performance. Overall, a simple yet versatile strategy is introduced that leads to environmentally resilient ionogels to meet the requirements of next-generation electroactive devices.     

Largely Promoted Mechano-Electrochemical Coupling Properties of Solid Polymer Electrolytes by Introducing Hydrogen Bonds-Rich Network

Solid polymer electrolytes (SPEs) and their composites are the most promising spices to access the commercial application in all-solid-state lithium batteries, where definite requirements for SPEs should be satisfied including moderate mechanical strength, high Li-ion conductivity, and stable electrode/electrolyte interface. Herein, polyurethane-based polymer (PNPU) is designed to further construct the hybrid solid polymer electrolyte (named as PNPU-PVDF-HFP) with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) for high energy density solid-state lithium metal batteries. The theoretical calculation and characterization demonstrate that PNPU-PVDF-HFP SPEs still maintain the multiple hydrogen bonding modes of PNPU, which contributes a significantly improved mechanical properties of the polymer membrane with compact structure. Moreover, it is corroborated that PNPU is involved to form the double Li⁺ transport paths in the hybrid electrolyte, accelerating the migration of lithium ions. Therefore, PNPU-PVDF-HFP SPEs are achieved with suitable tensile strength of 5.16 MPa and high elongation of 140.8%, high ambient ionic conductivity of 4.13 × 10⁻⁴ S cm⁻¹, excellent ductile, and stability on the interface of lithium metal anode. The Li/ LiFePO₄ and Li/Li[Ni_0.8Co_0.1Mn_0.1]O₂ solid-state batteries using PNPU-PVDF-HFP SPEs present a stable cycling performance at 30 °C. This study provides a feasible strategy to achieve mechano-electrochemical coupling stable SPEs for solid-state batteries.     

Polyether-b-Amide Based Solid Electrolytes with Well-Adhered Interface and Fast Kinetics for Ultralow Temperature Solid-State Lithium Metal Batteries

Solid-state lithium metal batteries (SSLMBs) are highly desirable for energy storage because of the urgent need for higher energy density and safer batteries. However, it remains a critical challenge for stable cycling of SSLMBs at low temperature. Here, a highly viscoelastic polyether-b-amide (PEO-b-PA) based composite solid-state electrolyte is proposed through a one-pot melt processing without solvent to address this key process. By adjusting the molar ratio of PEO-b-PA to lithium bis(trifluoromethanesulphonyl)imide (ethylene oxide:Li = 6:1) and adding 20 wt.% succinonitrile, fast Li⁺ transport channel is conducted within the homogeneous polymer electrolyte, which enables its application at ultra-low temperature (−20 to 25 °C). The composite solid-state electrolyte utilizes dynamic hydrogen-bonding domains and ion-conducting domains to achieve a low interfacial charge transfer resistance (<600 Ω) at −20 °C and high ionic conductivity (25 °C, 3.7 × 10⁻⁴ S cm⁻¹). As a result, the LiFePO₄|Li battery based on composite electrolyte exhibits outstanding electrochemical performance with 81.5% capacity retention after 1200 cycles at −20 °C and high discharge specific capacities of 141.1 mAh g⁻¹ with high loading (16.1 mg cm⁻²) at 25 °C. Moreover, the solid-state SNCM811|Li cell achieves excellent safety performance under nail penetration test, showing great promise for practical application.     

Towards All-Solid-State Polymer Batteries: Going Beyond PEO with Hybrid Concepts

To go beyond polyethylene oxide in lithium metal batteries, a hybrid polymer/oligomer cell design is presented, where an ester oligomer provides high ionic conductivity of 0.2 mS cm⁻¹ at 40 °C within thicker composite cathodes with active mass loadings of up to 11 mg cm⁻² (LiNbO₃-coated) LiNi_0.6Mn_0.2Co_0.2 (NMC622), while a 30 µm thin scaffold-supported polymer electrolyte affords mechanical stability. Corresponding discharge capacities of the hybrid cells exceed 170 mAh g⁻¹ (11 mg cm⁻²) or 160 mAh g⁻¹ (6 mg cm⁻²) at rates of either 0.1 or 0.25 C. Multilayer pouch cells are projected to enable energy densities of 235 Wh L⁻¹ (6 mg cm⁻²) and even up to 356 Wh L⁻¹ (11 mg cm⁻²), clearly superior to other reported polymer-based cell designs. Polyester electrolytes are environmentally benign and safer compared to common liquid electrolytes, while the straightforward synthesis and affordability of precursors render hybrid polyester electrolytes suitable candidates for future application in solid-state lithium metal batteries.     

Nanocellulose-Carboxymethylcellulose Electrolyte for Stable,High-Rate Zinc-Ion Batteries

Aqueous Zn ion batteries (ZIBs) are one of the most promising battery chemistries for grid-scale renewable energy storage. However, their application is limited by issues such as Zn dendrite formation and undesirable side reactions that can occur in the presence of excess free water molecules and ions. In this study, a nanocellulose-carboxymethylcellulose (CMC) hydrogel electrolyte is demonstrated that features stable cycling performance and high Zn²⁺ conductivity (26 mS cm⁻¹), which is attributed to the material's strong mechanical strength (≈70 MPa) and water-bonding ability. With this electrolyte, the Zn-metal anode shows exceptional cycling stability at an ultra-high rate, with the ability to sustain a current density as high as 80 mA cm⁻² for more than 3500 cycles and a cumulative capacity of 17.6 Ah cm⁻² (40 mA cm⁻²). Additionally, side reactions, such as hydrogen evolution and surface passivation, are substantially reduced due to the strong water-bonding capacity of the CMC. Full Zn||MnO₂ batteries fabricated with this electrolyte demonstrate excellent high-rate performance and long-term cycling stability (>500 cycles at 8C). These results suggest the cellulose-CMC electrolyte as a promising low-cost, easy-to-fabricate, and sustainable aqueous-based electrolyte for ZIBs with excellent electrochemical performance that can help pave the way toward grid-scale energy storage for renewable energy sources.     

A Supertough,Nonflammable, Biomimetic Gel with Neuron-Like Nanoskeleton for Puncture-Tolerant Safe Lithium Metal Batteries

To overcome the critical safety and performance issues of lithium metal batteries, it is urgent to develop advanced electrolytes with multi-defensive properties against fire, mechanical puncture, and dendrite growth simultaneously, in addition to high ion-conductivity. However, realizing these essential properties by one electrolyte has proved to be extremely challenging due to the inherent conflicts among them. Herein, to circumvent this challenge, a neuron-like gel polymer electrolyte (simply referred as Neu-PE) to simultaneously achieve supertoughness, nonflammability, dendrite-suppression capability and self-driven property is reported. This Neu-PE takes advantage of nano-phase separation regulated by highly ion-conductive deep-eutectic solvent. As a result, the Neu-PE holds high ambient ionic conductivity (1.27±0.09 mS cm⁻¹), super-toughness and strength (22.52 MJ m⁻³ and 13.5±0.6 MPa), fire resistance and importantly, lithium-metal anode protection capability. Lithium metal batteries assembled with this multi-defensive Neu-PE can work normally even under metal-probe puncture or serious damage by cutting.     

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.