Sandwich-Structured Quasi-Solid Polymer Electrolyte Enables High-Capacity,Long-Cycling,and Dendrite-Free Lithium Metal Battery at Room Temperature

The insufficient ionic conductivity, limited lithium-ion transference number (t_Li+), and high interfacial impedance severely hinder the practical application of quasi-solid polymer electrolytes (QSPEs). Here, a sandwich-structured polyacrylonitrile (PAN) based QSPE is constructedin which MXene-SiO₂ nanosheets act as a functional filler to facilitate the rapid transfer of lithium-ion in the QSPE, and a polymer and plastic crystalline electrolyte (PPCE) interface modification layer is coated on the surface of the PAN-based QSPE of 3 wt.% MXene-SiO₂ (SS-PPCE/PAN-3%) to reduce interfacial impedance. Consequently, the synthesized SS-PPCE/PAN-3% QSPE delivers a promising ionic conductivity of ≈1.7 mS cm⁻¹ at 30 °C, a satisfactory t_Li+ of 0.51, and a low interfacial impedance. As expected, the assembled Li symmetric battery with SS-PPCE/PAN-3% QSPE can stably cycle more than 1550 h at 0.2 mA cm⁻². The Li||LiFePO₄ quasi-solid-state lithium metal battery (QSSLMB) of this QSPE exhibits a high capacity retention of 81.5% after 300 cycles at 1.0 C and at RT. Even under the high-loading cathode (LiFePO₄ ≈ 10.0 mg cm⁻²) and RT, the QSSLMB achieves a superior area capacity and good cycling performance. Besides, the assembled high voltage Li||NMC811(loading ≈ 7.1 mg cm⁻²) QSSLMB has potential applications in high-energy fields.     

Dual-Conductive CoSe2@TiSe2-C Heterostructures Promoting Overall Sulfur Redox Kinetics under High Sulfur Loading and Lean Electrolyte

Although lithium–sulfur batteries (LSBs) possess a high theoretical specific capacity and energy density, the inherent problems including sluggish sulfur conversion kinetics and the shuttling of soluble lithium polysulfides (LiPSs) have severely hindered the development of LSBs. Herein, cobalt selenide (CoSe₂) polyhedrons anchored on few-layer TiSe₂-C nanosheets derived from Ti₃C₂T_x MXenes (CoSe₂@TiSe₂-C) are reported for the first time. The dual-conductive CoSe₂@TiSe₂-C heterostructures can accelerate the conversion reaction from liquid LiPSs to solid Li₂S and promote Li₂S dissociation process through high conductivity and lowered reaction energy barriers for promoting overall sulfur redox kinetics, especially under high sulfur loadings and lean electrolyte. Electrochemical analysis and density functional theory calculation results clearly reveal the catalytic mechanisms of the CoSe₂@TiSe₂-C heterostructures from the electronic structure and atomic level. As a result, the cell with CoSe₂@TiSe₂-C interlayer maintains a superior cycling performance with 842.4 mAh g⁻¹ and a low-capacity decay of 0.031% per cycle over 800 cycles at 1.0 C under a sulfur loading of 2.5 mg cm⁻². More encouragingly, it with a high sulfur loading of ≈7.0 mg cm⁻² still harvests a high areal capacity of ≈6.25 mAh cm⁻² under lean electrolyte (electrolyte/sulfur, E/S ≈ 4.5 µL mg⁻¹) after 50 cycles at 0.05 C.     

High-Safety and High-Energy-Density Lithium Metal Batteries in a Novel Ionic-Liquid Electrolyte

Rechargeable lithium metal batteries are next generation energy storage devices with high energy density, but face challenges in achieving high energy density, high safety, and long cycle life. Here, lithium metal batteries in a novel nonflammable ionic-liquid (IL) electrolyte composed of 1-ethyl-3-methylimidazolium (EMIm) cations and high-concentration bis(fluorosulfonyl)imide (FSI) anions, with sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) as a key additive are reported. The Na ion participates in the formation of hybrid passivation interphases and contributes to dendrite-free Li deposition and reversible cathode electrochemistry. The electrolyte of low viscosity allows practically useful cathode mass loading up to ≈16 mg cm⁻². Li anodes paired with lithium cobalt oxide (LiCoO₂) and lithium nickel cobalt manganese oxide (LiNi_0.8Co_0.1Mn_0.1O₂, NCM 811) cathodes exhibit 99.6–99.9% Coulombic efficiencies, high discharge voltages up to 4.4 V, high specific capacity and energy density up to ≈199 mAh g⁻¹ and ≈765 Wh kg⁻¹ respectively, with impressive cycling performances over up to 1200 cycles. Highly stable passivation interphases formed on both electrodes in the novel IL electrolyte are the key to highly reversible lithium metal batteries, especially for Li–NMC 811 full 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.     

Multiscale Structural Engineering of Sulfur/Carbon Cathodes Enables High Performance All-Solid-State Li?S Batteries

Constructing all-solid-state lithium–sulfur batteries (ASSLSBs) cathodes with efficient charge transport and mechanical flexibility is challenging but critical for the practical applications of ASSLSBs. Herein, a multiscale structural engineering of sulfur/carbon composites is reported, where ultrasmall sulfur nanocrystals are homogeneously anchored on the two sides of graphene layers with strong S C bonds (denoted as S@EG) in chunky expanded graphite particles via vapor deposition method. After mixing with Li_9.54Si_1.74P_1.44S_11.7Cl_0.3 (LSPSCL) solid electrolytes (SEs), the fabricated S@EG-LSPSCL cathode with interconnected “Bacon and cheese sandwich” feature can simultaneously enhance electrochemical reactivity, charge transport, and chemomechanical stability due to the synergistic atomic, nanoscopic and microscopic structural engineering. The assembled InLi/LSPSCL/S@EG-LSPSCL ASSLSBs demonstrate ultralong cycling stability over 2400 cycles with 100% capacity retention at 1 C, and a record-high areal capacity of 14.0 mAh cm⁻² at a record-breaking sulfur loading of 8.9 mg cm⁻² at room temperature as well as high capacities with capacity retentions of ≈100% after 600 cycles at 0 and 60 °C. Multiscale structural engineered sulfur/carbon cathode has great potential to enable high-performance ASSLSBs for energy storage applications.     

Sandwich Structured Metal oxide/Reduced Graphene Oxide/Metal Oxide-Based Polymer Electrolyte Enables Continuous Inorganic–Organic Interphase for Fast Lithium-Ion Transportation

Introducing inorganic fillers into organic poly(ethylene oxide)(PEO)-based electrolyte has attracted substantial attention to enhance its ionic conductivity and mechanical strength, but limited inorganic–organic interphases are always caused by isolated particles agglomeration. Herein, a variety of sandwich structured metal oxide/reduced graphene oxide(rGO)/metal oxide nanocomposites to optimize lithium-ion conduction by interconnected amorphous organic–inorganic interphases in lithium metal batteries, are proposed. With the support of high surface area rGO, the agglomeration of metal oxide particles is precluded, forming continuous amorphous organic–inorganic interphases with stacked layer-by-layer structure, thus creating 3D interconnected lithium-ion transportation channels vertically and laterally. Besides, metal oxide nanoparticles with hydroxyls possess high affinity toward bis(tri-fluoromethanesulfonyl)imide anions by hydrogen bindings between hydroxyls and fluorine and metal-oxygen bonds, releasing more free lithium ions. Consequently, PEO-ZnO/rGO/ZnO electrolyte delivers superior ionic conductivity of 1.02 × 10⁻⁴ S cm⁻¹ at 25 °C and lithium-ion transference number of 0.38 at 60 °C. Furthermore, ZnO/rGO/ZnO insertion promotes the formation of LiF-rich stable solid electrolyte interface, endowing Li symmetric cells with long-term cycling stability over 900 hours. The corresponding LiFePO₄ cathode possesses a high reversible specific capacity of 130 mAh g⁻¹ at 0.5C after cycling 300 cycles with a poor capacity fading of 0.05% per cycle.     

Exfoliated Mesoporous 2D Covalent Organic Frameworks for High-Rate Electrochemical Double-Layer Capacitors

The electrochemical double-layer capacitors (EDLCs) are highly demanded electrical energy storage devices due to their high power density with thousands of cycle life compared with pseudocapacitors and batteries. Herein, a series of capacitor cells composed of exfoliated mesoporous 2D covalent organic frameworks (e-COFs) that are able to perform excellent double-layer charge storage is reported. The selected mesoporous 2D COFs possess eclipsed AA layer-stacking mode with 3.4 nm square-like open channels, favorable BET surface areas (up to 1170 m² g⁻¹), and high thermal and chemical stabilities. The COFs via the facile, scalable, and mild chemical exfoliation method are further exfoliated to produce thin-layer structure with average thickness of about 22 nm. The e-COF-based capacitor cells achieve high areal capacitance (5.46 mF cm⁻² at 1,000 mV s⁻¹), high gravimetric power (55 kW kg⁻¹), and relatively low τ₀ value (121 ms). More importantly, they perform nearly an ideal DL charge storage at high charge–discharge rate (up to 30 000 mV s⁻¹) and maintain almost 100% capacitance stability even after 10 000 cycles. This study thus provides insights into the potential utilization of COF materials for EDLCs.     

Construction of Inorganic/Organic Hybrid Layer for Stable Na Metal Anode Operated under Wide Temperatures

Sodium metal battery is supposed to be a propitious technology for high-energy storage application owing to the advantages of natural abundance and low cost. Unfortunately, the uncontrollable dendrite growth critically hampers its practical implementation. Herein, an inorganic/organic hybrid layer of NaF/C F/CC on the surface of Na foil (IOHL-Na) is designed and synthesized through the in situ reaction of polyvinylidene fluoride (PVDF) and metallic sodium. This protective layer possesses satisfactory Young's modulus, good kinetic property, and sodiophilicity, which can distinctly stabilize Na metal anode. As a result, the symmetric IOHL-Na cell achieves a lifespan of 770 h at 1 mAh cm⁻²/1 mA cm⁻² in carbonate electrolyte. The assembled full battery of IOHL-Na||Na₃V₂(PO₄)₃ delivers a high discharge capacity of 85 mAh g⁻¹ at 10 C after 600 cycles under ambient temperature. Furthermore, the IOHL-Na||Na₃V₂(PO₄)₃ cell still can steadily operate at 10 C for 600 cycles at 55 °C. And when testing at an ultralow temperature of −40 °C, the full cell achieves 40 mAh g⁻¹ at 0.5 C with a prolonged lifespan of 450 cycles. This work offers a new approach to protect the metal sodium anode without dendrite growth under wide temperatures.     

Rational Design of a High-Loading Polysulfide Cathode and a Thin-Lithium Anode for Developing Lean-Electrolyte Lithium–Sulfur Full Cells

Lithium-sulfur cells are attractive energy-storage systems because of their high energy density and the electrochemical utilization rates of the high-capacity lithium-metal anode and the low-cost sulfur cathode. The commercialization of high-performance lithium–sulfur cells with high discharge capacity and cyclic stability requires the optimization of practical cell-design parameters. Herein, a carbon structural material composed of a carbon nanotube skeleton entrapping conductive graphene is synthesized as an electrode substrate. The carbon structural material is optimized to develop a high-loading polysulfide cathode with a high sulfur loading capacity (6–12 mg cm⁻²), rate performance (C/10–C/2), and cyclic stability for 200 cycles. A thin lithium anode based on the carbon structural material is developed and exhibits long lithium stripping/plating stability for ≈2500 h with a lithium-ion transference number of 0.68. A lean-electrolyte lithium–sulfur full cell with a low electrolyte-to-sulfur ratio of 6 µL mg⁻¹ is constructed with the designed high-loading polysulfide cathode and the thin lithium anode. The integration of all the critical cell-design parameters endows the lithium–sulfur full cell with a low negative-to-positive capacity ratio of 2.4, while exhibiting stable cyclability with an initial discharge capacity of 550 mAh g⁻¹ and 60% capacity retention after 200 cycles.     

Molybdenum Atom Engineered Vanadium Disulfide for Boosted High-Capacity Li-Ion Storage

A drawback with lithium-ion batteries (LIBs) lies in the unstable lithium storage which results in poor electrochemical performance. Therefore, it's of importance to improve the electrochemical functionality and Li-ion transport kinetics of electrode materials for high-performance lithium storage. Here, a subtle atom engineering via injecting molybdenum (Mo) atoms into vanadium disulfide (VS₂) to boost high capacity Li-ion storage is reported. By combining operando, ex situ monitoring and theoretical simulation, it is confirmed that the 5.0%Mo atoms impart flower-like VS₂ with expanded interplanar spacing, lowered Li-ion diffusion energy barrier, and increased Li-ion adsorption property, together with enhanced e⁻ conductivity, to boost Li-ion migration. A “speculatively” optimized 5.0% Mo-VS₂ cathode that exhibits a specific capacity of 260.8 mA h g⁻¹ at 1.0 A g⁻¹ together with a low decay of 0.009% per cycle over 500 cycles is demonstrated. It is shown that this value is ≈1.5 times compared with that for bare VS₂ cathode. This investigation has substantiated the Mo atom doping can effectively guide the Li-ion storage and open new frontiers for exploiting high-performance transition metal dichalcogenides for LIBs.     

3D Co-Doping α-Ni(OH)2 Nanosheets for Ultrastable,High-Rate Ni-Zn Battery

The α-Ni(OH)₂ is regarded as one promising cathode for aqueous nickel-zinc batteries due to its high theoretical capacity of ≈480 mAh g⁻¹, its practical deployment however suffers from the poor stability in strong alkaline solution, intrinsic low electrical conductivity as well as the retarded ionic diffusion. Herein, a 3D (three dimensional) macroporous α-Ni(OH)₂ nanosheets with Co doping is designed through a facile and easily scalable electroless plating combined with electrodeposition strategy. The unique micrometer-sized 3D pores come from Ni substrate and rich voids between Co-doping α-Ni(OH)₂ nanosheets can synergistically afford facile, interconnected ionic diffusion channels, sufficient free space for accommodating its volume changes during cycling; meanwhile, the Co-doping can stabilize the structural robustness of the α-Ni(OH)₂ in the alkaline electrolyte during cycling. Thus, the 3D α-Ni(OH)₂ shows a high capacity of 284 mAh g⁻¹ at 0.5 mA cm⁻² with an excellent retention of 78% even at 15 mA cm⁻², and more than 2000 stable cycles at 6 mA cm⁻², as well as the robust cycling upon various flexible batteries. This work provides a simple and efficient pathway to enhance the electrochemical performance of Ni-Zn batteries through improving ionic transport kinetics and stabilizing crystal structure of cathodes.     

Simultaneous High Ionic Conductivity and Lithium-Ion Transference Number in Single-Ion Conductor Network Polymer Enabling Fast-Charging Solid-State Lithium Battery

Developing solid-state electrolyte with sufficient ionic conduction and flexible-intimate interface is vital to advance fast-charging solid-state lithium batteries. Solid polymer electrolyte yields the promise of interfacial compatibility, yet its critical bottleneck is how to simultaneously achieve high ionic conductivity and lithium-ion transference number. Herein, single-ion conducting network polymer electrolyte (SICNP) enabling fast charging is proposed to positively realize fast lithium-ion locomotion with both high ionic conductivity of 1.1 × 10⁻³ S cm⁻¹ and lithium-ion transference number of 0.92 at room temperature. Experimental characterization and theoretical simulations demonstrate that the construction of polymer network structure for single-ion conductor not only facilitates fast hopping of lithium ions for boosting ionic kinetics, but also enables a high dissociation level of the negative charge for lithium-ion transference number close to unity. As a result, the solid-state lithium batteries constructed by coupling SICNP with lithium anodes and various cathodes (e.g., LiFePO₄, sulfur, and LiCoO₂) display impressive high-rate cycling performance (e.g., 95% capacity retention at 5 C for 1000 cycles in LiFePO₄|SICNP|lithium cell) and fast-charging capability (e.g., being charged within 6 min and discharged over than 180 min in LiCoO₂|SICNP|lithium cell). Our study provides a prospective direction for solid-state electrolyte that meets the lithium-ion dynamics for practical fast-charging solid-state lithium batteries.     

Efficient Regulation of Polysulfides by MoS2/MoO3 Heterostructures for High-Performance Li-S Batteries

The notorious shuttle effect and sluggish conversion of polysulfides seriously hinder the practical application of Lithium-sulfur (Li-S) batteries. In this study, a novel architecture of MoS₂/MoO₃ heterostructure uniformly distributed on carbon nanotubes (MoS₂/MoO₃@CNT) is designed and introduced into Li-S batteries via decorating commercial separator to regulate the redox reactions of polysulfides. Systematic experiments and theoretical calculations showed that the heterostructure not only provides sufficient surface affinity to capture polysulfides and acts as an active catalyst to promote the conversion of polysulfides, but also the highly conductive CNT enables rapid electron/ion migration. As a result, Li-S batteries with the MoS₂/MoO₃@CNT-PP separator deliver an impressive reversible capacity (1015 mAh g⁻¹ at 0.2 A g⁻¹ after 100 cycles), excellent rate capacity (873 mAh g⁻¹ at 5 A g⁻¹), and low self-discharge capacity loss (94.6% capacity retention after 7 days of standing). Moreover, even at an elevated temperature of 70 °C, it still exhibits high-capacity retention (800 mAh g⁻¹ at 1 A g⁻¹ after 100 cycles). Encouragingly, when the sulfur load is increased to 8.7 mg cm⁻², the high reversible areal capacity of 6.61 mAh cm⁻² can be stably maintained after 100 cycles, indicating a high potential for practical application.     

Thickness-Controlled Synthesis of Compact and Uniform MOF Protective Layer for Zinc Anode to Achieve 85% Zinc Utilization

Zinc anode-based aqueous batteries have attracted considerable interest for large-scale energy storage and wearable devices. Unfortunately, the formation of Zn dendrite, parasitic hydrogen evolution reaction (HER), and irreversible by-products, seriously restrict their practical applications. Herein, a series of compact and uniform metal-organic frameworks (MOFs) films with precisely controlled thickness (150–600 nm) are constructed by a pre-oxide gas deposition (POGD) method on Zn foil. Under the protection of MOF layer with optimum thickness, the corrosion of zinc, the side reaction of hydrogen evolution, and the growth of dendrites on the zinc surface are suppressed. The symmetric cell based on Zn@ZIF-8 anode exhibits exceptional cyclicality for over 1100 h with low voltage hysteresis of≈38 mV at 1 mA cm⁻². Even at current densities of 50 mA cm⁻² with an area capacity of 50 mAh cm⁻² (85% Zn utilization), the electrode can keep cycling for >100 h. Besides, this Zn@ZIF-8 anode also delivers a high average CE of 99.4% at 1 mA cm⁻². Moreover, a rechargeable Zn ion battery is fabricated based on the Zn@ZIF-8 anode and MnO₂ cathode, which presents an exceptionally long lifespan with no capacity attenuation for 1000 cycles.     

Homogenizing Zn Deposition in Hierarchical Nanoporous Cu for a High-Current,High Areal-Capacity Zn Flow Battery

A Zn anode can offset the low energy density of a flow battery for a balanced approach toward electricity storage. Yet, when targeting inexpensive, long-duration storage, the battery demands a thick Zn deposit in a porous framework, whose heterogeneity triggers frequent dendrite formation and jeopardizes the stability of the battery. Here, Cu foam is transferred into a hierarchical nanoporous electrode to homogenize the deposition. It begins with alloying the foam with Zn to form Cu₅Zn₈, whose depth is controlled to retain the large pores for a hydraulic permeability ≈10⁻¹¹ m². Dealloying follows to create nanoscale pores and abundant fine pits below 10 nm, where Zn can nucleate preferentially due to the Gibbs–Thomson effect, as supported by a density functional theory simulation. Morphological evolution monitored by in situ microscopy confirms uniform Zn deposition. The electrode delivers 200 h of stable cycles in a Zn–I₂ flow battery at 60 mAh cm⁻² and 60 mA cm⁻², performance that meets practical demands.     

Lithium Azides Induced SnS Quantum Dots for Ultra-Fast and Long-Term Sodium Storage

Tin sulfide (SnS) is an attractive anode for sodium ion batteries (NIBs) because of its high theoretical capacity, while it seriously suffers from the inherently poor conductivity and huge volume variation during the cycling process, leading to inferior lifespan. To intrinsically maximize the sodium storage of SnS, herein, lithium azides (LiN₃)-induced SnS quantum dots (QDs) are first reported using a simple electrospinning strategy, where SnS QDs are uniformly distributed in the carbon fibers. Taking the advantage of LiN₃, which can effectively prevent the growth of crystal nuclei during the thermal treatment, the well-dispersed SnS QDs performs superior Na⁺ transfer kinetics and pseudocapacitive when used as an anode material for NIBs. The 3D SnS quantum dots embedded uniformly in N-doped nanofibers (SnS QDs@NCF) electrodes display superior long cycling life-span (484.6 mAh g⁻¹ after 5800 cycles at 2 A g⁻¹ and 430.9 mAh g⁻¹ after 7880 cycles at 10 A g⁻¹), as well as excellent rate capability (422.3 mAh g⁻¹ at 20 A g⁻¹). This fabrication of transition metal sulfides QDs composites provide a feasible strategy to develop NIBs with long life-span and superior rate capability to pave its practical implementation.     

Enhanced Interfacial Magnetization is Responsible for the Negative Capacity Fading of Cobalt Ditelluride Anodes for Lithium Storage

In lithium-ion batteries (LIBs), the stabilized capacities of transition metal compound anodes usually exhibit higher values than their theoretical values due to the interfacial charge storage, the formation of reversible electrolyte-derived surface layer, or interfacial magnetization. But the effectively utilizing the mechanisms to achieve novel anodes is rarely explored. Herein, a novel nanosized cobalt ditelluride (CoTe₂) anodes with ultra-high capacity and long term stability is reported. Electrochemical tests show that the lithium storage capacity of the best sample reaches 1194.7 mA h g⁻¹ after 150 cycles at 0.12 A g⁻¹, which increases by 57.8% compared to that after 20 cycles. In addition, the sample offers capacities of 546.6 and 492.1 mA h g⁻¹ at 0.6 and 1.8 A g⁻¹, respectively. During cycles, CoTe₂ particles (average size 20 nm) are gradually pulverized into the smaller nanoparticles (<3 nm), making the magnetization more fully due to the larger contact area of Co/Li₂Te interface, yielding an increased capacity. The negative capacity fading is observed, and verified by ex situ structural characterizations and in situ electrochemical measurements. The proposed strategy can be further extended to obtain other high-performance ferromagnetic metal based electrodes for energy storage applications.     

Synergistically Accelerating Adsorption-Electrocataysis of Sulfur Species via Interfacial Built-In Electric Field of SnS2-MXene Mott–Schottky Heterojunction in Li-S Batteries

Developing efficient heterojunction electrocatalysts and uncovering their atomic-level interfacial mechanism in promoting sulfur-species adsorption-electrocatalysis are interesting yet challenging in lithium-sulfur batteries (LSBs). Here, multifunctional SnS₂-MXene Mott–Schottky heterojunctions with interfacial built-in electric field (BIEF) are developed, as a model to decipher their BIEF effect for accelerating synergistic adsorption-electrocatalysis of bidirectional sulfur conversion. Theoretical and experimental analysis confirm that because Ti atoms in MXene easily lost electrons, whereas S atoms in SnS₂ easily gain electrons, and under Mott–Schottky influence, SnS₂-MXene heterojunction forms the spontaneous BIEF, leading to the electronic flow from MXene to SnS₂, so SnS₂ surface easily bonds with more lithium polysulfides. Moreover, the hetero-interface quickly propels abundant Li⁺/electron transfer, so greatly lowering Li₂S nucleation/decomposition barrier, promoting bidirectional sulfur conversion. Therefore, S/SnS₂-MXene cathode displays a high reversible capacity (1,188.5 mAh g⁻¹ at 0.2 C) and a stable long-life span with 500 cycles (≈82.7% retention at 1.0 C). Importantly, the thick sulfur cathode (sulfur loading: 8.0 mg cm⁻²) presents a large areal capacity of 7.35 mAh cm⁻² at lean electrolyte of 5.0 µL mg_s⁻¹. This work verifies the substantive mechanism that how BIEF optimizes the catalytic performance of heterojunctions and provides an effective strategy for deigning efficient bidirectional Li-S catalysts in LSBs.     

Exploiting High-Voltage Stability of Dual-Ion Aqueous Electrolyte Reinforced by Incorporation of Fiberglass into Zwitterionic Hydrogel Electrolyte

Rechargeable zinc aqueous batteries are key alternatives for replacing toxic, flammable, and expensive lithium-ion batteries in grid energy storage systems. However, these systems possess critical weaknesses, including the short electrochemical stability window of water and intrinsic fast zinc dendrite growth. Hydrogel electrolytes provide a possible solution, especially cross-linked zwitterionic polymers that possess strong water retention ability and high ionic conductivity. Herein, an in situ prepared fiberglass-incorporated dual-ion zwitterionic hydrogel electrolyte with an ionic conductivity of 24.32 mS cm⁻¹, electrochemical stability window up to 2.56 V, and high thermal stability is presented. By incorporating this hydrogel electrolyte of zinc and lithium triflate salts, a zinc//LiMn_0.6Fe_0.4PO₄ pouch cell delivers a reversible capacity of 130 mAh g⁻¹ in the range of 1.0–2.2 V at 0.1C, and the test at 2C provides an initial capacity of 82.4 mAh g⁻¹ with 71.8% capacity retention after 1000 cycles with a coulombic efficiency of 97%. Additionally, the pouch cell is fire resistant and remains safe after cutting and piercing.     

Entropy-Driven Ultrafast Ion Conduction Via Confining Organic Plastic Crystals in Ordered Nanochannels of Covalent Organic Frameworks

Low conductivity over a wide temperature region due to ultra-slow ion migration dynamics is a key issue in the field of solid-state electrolytes (SSE), which needs to be solved and improved. Covalent organic frameworks (COFs), a rapidly growing class of porous crystalline materials, emerge as a new research hotspot in the field of SSEs. This is due to their homogeneously dispersed sites and well-defined pathways for ion diffusion, demonstrating great advantages over conventional non-porous solids. Herein, a composite solid electrolyte by confining organic ionic plastic crystal (OIPC) in the 1D ordered nanochannels of COFs as the host matrix for solid-state lithium-ion conduction, is reported. Due to the loss of coupling between PBu₄⁺ cations and TFSI⁻ anions, the cation–anion interaction is weakened; and thus, the lithium-ion transportation is facilitated. As a result, the COF-confining OIPC SSEs show ultra-high lithium-ion conductivity of 0.048 S cm⁻¹ at 30 °C and 0.021 S cm⁻¹ at the extremely low temperature of −30 °C. The dynamic origin of this fast ion conduction is characterized by differential scanning calorimetry (DSC), X-ray photoelectron spectroscopy (XPS), and variable temperature solid-state nuclear magnetic resonance (NMR) spectroscopy.