Solid Polymer Electrolytes with Enhanced Electrochemical Stability for High-Capacity Aluminum Batteries

Chloroaluminate ionic liquids are commonly used electrolytes in rechargeable aluminum batteries due to their ability to reversibly electrodeposit aluminum at room temperature. Progress in aluminum batteries is currently hindered by the limited electrochemical stability, corrosivity, and moisture sensitivity of these ionic liquids. Here, a solid polymer electrolyte based on 1-ethyl-3-methylimidazolium chloride-aluminum chloride, polyethylene oxide, and fumed silica is developed, exhibiting increased electrochemical stability over the ionic liquid while maintaining a high ionic conductivity of ≈13 mS cm⁻¹. In aluminum–graphite cells, the solid polymer electrolytes enable charging to 2.8 V, achieving a maximum specific capacity of 194 mA h g⁻¹ at 66 mA g⁻¹. Long-term cycling at 2.7 V showed a reversible capacity of 123 mA h g⁻¹ at 360 mA g⁻¹ and 98.4% coulombic efficiency after 1000 cycles. Solid-state nuclear magnetic resonance spectroscopy measurements reveal the formation of five-coordinate aluminum species that crosslink the polymer network to enable a high ionic liquid loading in the solid electrolyte. This study provides new insights into the molecular-level design and understanding of polymer electrolytes for high-capacity aluminum batteries with extended potential limits.     

Fast Charge-Transfer Rates in Li-CO2 Batteries with a Coupled Cation-Electron Transfer Process

Li-CO₂ batteries with a high theoretical energy density (1876 Wh kg⁻¹) have unique benefits for reversible carbon fixation for energy storage systems. However, due to lack of stable and highly active catalysts, the long-term operation of Li-CO₂ batteries is limited to low current densities (mainly <0.2 mA cm⁻²) that are far from practical conditions. In this work, it is discovered that, with an ionic liquid-based electrolyte, highly active and stable transition metal trichalcogenide alloy catalysts of Sb_0.67Bi_1.33X₃ (X = S, Te) enable operation of the Li-CO₂ battery at a very high current rate of 1 mA cm⁻² for up to 220 cycles. It is revealed that: i) the type of chalcogenide (Te vs S) significantly affects the electronic and catalytic properties of the catalysts, ii) a coupled cation-electron charge transfer process facilitates the carbon dioxide reduction reaction (CO₂RR) occurring during discharge, and iii) the concentration of ionic liquid in the electrolyte controls the number of participating CO₂ molecules in reactions. A combination of these key factors is found to be crucial for a successful operation of the Li-CO₂ chemistry at high current rates. This work introduces a new class of catalysts with potential to fundamentally solve challenges of this type of batteries.     

CO2-Etching Creates Abundant Closed Pores in Hard Carbon for High-Plateau-Capacity Sodium Storage

Hard carbon (HC) has become the most promising anode material for sodium-ion batteries (SIBs), but its plateau capacity at ≈0.1 V (Na⁺/Na) is still much lower than that of graphite (372 mAh g⁻¹) in lithium-ion batteries (LIBs). Herein, a CO₂-etching strategy is applied to generate abundant closed pores in starch-derived hard carbon that effectively enhances Na⁺ plateau storage. During CO₂ etching, open pores are first formed on the carbon matrix, which are in situ reorganized to closed pores through high-temperature carbonization. This CO₂-assisted pore-regulation strategy increases the diameter and the capacity of closed pores in HC, and simultaneously maintains the microsphere morphology (10–30 µm in diameter). The optimal HC anode exhibits a Na-storage capacity of 487.6 mAh g⁻¹ with a high initial Coulomb efficiency of 90.56%. A record-high plateau capacity of 351 mAh g⁻¹ is achieved, owing to the abundant closed micropores generated by CO₂-etching. Comprehensive in situ and ex situ tests unravel that the high Na⁺ storage performance originates from the pore-filling mechanism in the closed micropores.     

A Safe Organic/Inorganic Composite Anode for Sodium-Ion Batteries

Sodium-ion batteries (SIBs), based on hard carbon anodes and Na⁺-intercalation compound cathodes, have gained significant attention. Nonetheless, hard carbon anodes involve the storage of Na⁺ at a low potential, typically below 0.1 V (vs Na/Na⁺), which increases the risk of dendritic Na growth on the anode surface during overcharging. Herein, a safe organic/inorganic composite anode containing tetrasodium 3,4,9,10-perylenetetracarboxylate (Na₄PTC) and Metallic bismuth (Bi) with a weight ratio of 7:2, which exhibits an average potential of 0.7 V (vs Na⁺/Na) and a capacity of 150 mAh g⁻¹ is proposed. The electrode reaction involves a reversible coordination reaction within the organic host and alloying reactions within the metallic Bi component. Importantly, the organic component efficiently buffers the volume changes in Bi during the alloying reaction, while the metallic Bi enhances the electronic conductivity of the organic material. As a result, this composite anode shows high cycle stability and rate performance, even under high mass loadings ranging from 10 to 50 mg cm⁻². Furthermore, it is demonstrated that the Na-ion full cell, consisting of the composite anode and the Na₃V₂O₂(PO₄)₂F cathode, exhibits minimal capacity degradation over 100 cycles while maintaining a high areal capacity of 1.1 mA cm⁻².     

Minutes-Fast Production of Vacancy-Enriched MXenes as an Efficient Platform for Single-Atom Electrocatalysts

Although MXenes have been synthesized by liquid phase and molten salt etching approaches, it still suffers from sluggish reaction kinetics of removing A species from MAX phases associated with an overlong production time (5–48 h). Here, a minute-level production approach is developed to produce MXenes (Ti₂CCl_x) by selectively etching MAX phases (Ti₂AlC) under metal chloride (ZnCl₂) vapor. In this synthetic protocol, metal chloride vapor possesses a very high chemical activity to the interlaminar A metal layers of MAX phases owing to negative Gibbs free energies, accompanied with the fast removal of gaseous A-containing chlorides in the reaction system. Moreover, some M species can be controllably etched off from the lattice of MX slabs to generate metal vacancies, which have a high reducing ability to implant single-atom Zn from ZnCl₂ vapor. Finally, vacancy-enriched MXenes are produced after the volatilization of Zn. In this manner, the etching time is less than one-sixtieth those of liquid phase and molten salt etching approaches. The resultant MXenes can be employed as an efficient platform for implanting single-atom Pt, showing a low overpotential of 41 mV at a current density of 10 mA cm⁻² and a good long-term stability up to 5000 cycles.     

In Situ Vertically Aligned MoS2 Arrays Electrodes for Complexing Agent-Free Bromine-Based Flow Batteries with High Power Density and Long Lifespan

Bromine-based flow batteries (Br-FBs) are highly competitive for stationary energy storage due to their high energy density and cost-effectiveness. However, adding bromine complexing agents (BCAs) to electrolytes slows down Br₂/Br⁻ reaction kinetics, causing higher polarization and lower power density of Br-FBs. Herein, in situ vertically aligned MoS₂ nanosheet arrays on traditional carbon felt substrates as electrodes to construct high power–density BCA-free Br-FBs are proposed. MoS₂ arrays exhibit strong adsorption capacity to bromine, which helps the electrodes capture and retain bromine species. Even without BCAs, the battery self-discharge caused by bromine diffusion is also inhibited. Moreover, the rate-determining step of Br₂/Br⁻ reactions is boosted and the vertically aligned array structure provides sufficient sites, motivating Br₂/Br⁻ reaction kinetics and decreasing the battery polarization. The capacity retention rate of the BCA-free Br-FB based on MoS₂ arrays-based electrodes reaches 46.34% after the 24-h standing test at 80 mA cm⁻², meeting the requirements of practical applications. Most importantly, this BCA-free Br-FB exhibits a high Coulombic efficiency of 97.00% and an ultralong cycle life of 1000 cycles at a high current density of 200 mA cm⁻². This work provides an available approach to developing advanced electrode materials for high power–density and long-lifespan Br-FBs.     

Achieving a Quasi-Solid-State Conversion of Polysulfides via Building High Efficiency Heterostructure for Room Temperature Na–S Batteries

The practical application of room temperature sodium–sulfur (RT Na–S) batteries are prevented by the sulfur insulation, the severe shuttling effect of high-order sodium polysulfides (Na₂S_n, 4 ≤ n ≤ 8), and the sluggish reaction kinetics. Therefore, designing an ideal host material to suppress the polysulfides shuttle process and accelerate the redox reactions of soluble NaPSs to Na₂S₂/Na₂S is of paramount importance for RT Na–S batteries. Here, a quasi-solid-state transformation of NaPSs is realized by building high efficiency MoC-W₂C heterostructure in freestanding multichannel carbon nanofibers via electrospinning and calcination methods (MoC-W₂C-MCNFs). The multichannel carbon nanofibers are interlinked micro-mesoporous structures that can accommodate volume change of electrode materials and confine the entire redox process of NaPSs (restraining the polysulfides shuttle process). Meanwhile, the MoC-W₂C heterostructure with abundant heterointerfaces can facilitate electron/ion transport and accelerate conversion of NaPSs. Consequently, the S/MoC-W₂C-MCNFs cathode delivers a high capacity of 640 mAh g⁻¹ after 500 cycles at 0.2 A g⁻¹ and an excellent reversible performance of 200 mAh g⁻¹ after ultralong 3500 cycles at 4 A g⁻¹. What's more, the heterostructure catalytic mechanism (a quasi-solid-state transformation) is proposed and confirmed in carbonate electrolyte by combining experimentally and theoretically.     

Steel Anti-Corrosion Strategy Enables Long-Cycle Zn Anode

The progress of aqueous zinc batteries (AZBs) is limited by the poor cycling life due to Zn anode instability, including dendrite growth, surface corrosion, and passivation. Inspired by the anti-corrosion strategy of steel industry, a compounding corrosion inhibitor (CCI) is employed as the electrolyte additive for Zn metal anode protection. It is shown that CCI can spontaneously generate a uniform and ≈30 nm thick solid-electrolyte interphase (SEI) layer on Zn anode with a strong adhesion via Zn O bonding. This SEI layer efficiently prohibits water corrosion and guides homogeneous Zn deposition without obvious dendrite formation. This enables reversible Zn deposition and dissolution for over 1100 h under the condition of 1 mA cm⁻² and 1 mAh cm⁻² in symmetric cells. The Zn-MnO₂ full cells with CCI-modified electrolyte deliver an ultralow capacity decay rate (0.013% per cycle) at 0.5 A g⁻¹ over 1000 cycles. Such an innovative strategy paves a low-cost way to achieve AZBs with long lifespan.     

Inducing the Preferential Growth of Zn (002) Plane for Long Cycle Aqueous Zn-Ion Batteries

Uncontrolled growth of Zn dendrites is the main reason for the short-circuit failure of aqueous Zn-ion batteries. Using electrolyte additives to manipulate the crystal growth is one of the most convenient strategies to mitigate the dendrite issue. However, most additives would be unstable during cycling due to the structural reconstruction of the deposition layer. Herein, it is proposed to use 1-butyl-3-methylimidazolium cation (BMIm⁺ ion) as an electrolyte additive, which could steadily induce the preferential growth of (002) plane and inhibit the formation of Zn dendrites. Specifically, BMIm⁺ ion will be preferentially adsorbed on (100) and (101) planes of Zn anodes, forcing Zn²⁺ ion to deposit on the (002) plane, thus inducing the preferential growth of the (002) plane and forming a flat and compact deposition layer. As a result, the Zn anode cycles for 1000 h at10 mA cm⁻² and 10 mAh cm⁻² as well as a high Coulombic efficiency of 99.8%. Meanwhile, the NH₄V₄O₁₀||Zn pouch cell can operate stably for 240 cycles at 0.4 A g⁻¹. The BMIm⁺ ion additive keeps a stable effect on the structural reconstruction of the Zn anode during the prolonged cycling.     

KxVPO4F (x∼0): A New High-Voltage and Low-Stain Cathode Material for Ultrastable Calcium Rechargeable Batteries

The utilization of high-voltage intercalation cathodes in calcium-ion batteries (CIBs) is impeded by the substantial size and divalent character of Ca²⁺ ions, which result in pronounced volume alterations and sluggish ion mobility, consequently causing inferior reversibility and low energy/power densities. To tackle these issues, polyanionic K-vacant K_xVPO₄F (x∼0, designated as K₀VPF) is proposed as high-voltage and ultra-stable cathode material in CIBs. The K₀VPF demonstrates a decent calcium storage capacity of 75 mAh g⁻¹ at 10 mA g⁻¹ and remarkable capacity retention of 84.2% over 1000 cycles. The average working voltage of the K₀VPF is 3.85 V versus Ca²⁺/Ca, representing the highest value reported for CIB cathodes to date. The combined experimental and theoretical investigations revealed that the low volume changes and hopping diffusion barriers contribute to the extraordinary stability and high-power capabilities, respectively, of K₀VPF. The distribution of Ca ions into polyanionic frameworks with pronounced spatial separation effectively attenuates the Ca²⁺–Ca²⁺ repulsive force and thus augmenting the Ca migration kinetics. The high voltage of K₀VPF is attributed to the inductive effect from the largely electronegative fluorine. In conjunction with a calcium metal anode and a compatible electrolyte, Ca metal full cells featured a record-high energy density of ≈300 Wh kg⁻¹.     

An Iodine-Chemisorption Binder for High-Loading and Shuttle-Free Zn–Iodine Batteries

Aqueous zinc–iodine (Zn–I₂) batteries have attracted considerable research interest as an alternative energy storage system due to their high specific capacity, intrinsic safety, and low cost. However, the notorious shuttle effect of soluble polyiodides causes severe capacity loss and poor electrochemical reversibility, restricting their practical usage. Herein, this study reports a bifunctional binder (polyacrylonitrile copolymer, as known as LA133) with strong iodine-chemisorption capability for aqueous Zn–I₂ batteries to suppress polyiodide shuttling. From both calculation and experimental data, this study reveals that the amide and carboxyl groups in LA133 binder can strongly bond to polyiodides, significantly immobilizing them at cathode side. As a result, fewer byproducts, slower hydrogen evolution, and lesser Zn dendrite in the Zn–I₂ battery are observed. Consequently, the battery shows high specific capacity (202.8 mAh g⁻¹) with high iodine utilization efficiency (96.1%), and long cycling lifespan (2700 cycles). At the high mass loading of 7.82 mg cm⁻², the battery can still retain 83.3% of its initial capacity after 1000 cycles. The specific capacity based on total cathode slurry mass reaches 71.2 mAh g⁻¹, higher than most of the recent works. The strategy opens a new avenue to address the shuttling challenge of Zn–I₂ batteries through bifunctional binder.     

Self-Supported Catalytic Electrode of CoW/Co-Foam Achieves Efficient Ammonia Synthesis at Ampere-Level Current Density

Conversion of air and water into valuable chemicals of ammonia (NH₃) by plasma activation and electrochemical reduction is a promising approach to achieve zero carbon-emission synthesis of NH₃. However, designing highly efficient electrochemical catalysts is one of the key challenges in accomplishing this strategy. Herein, a self-supported cobalt–tungsten alloy supported on cobalt foam (CoW/CF) is developed via a simple and efficient method at room temperature. Surprisingly, the catalyst exhibits ultra-high NH₃ partial current density (1559 mA cm⁻²), superior NH₃ yield rate (164.3 mg h⁻¹ cm⁻²), and high Faradaic efficiency (98.1%) under the condition of 0.2 M nitrate/nitrite, outperforming most of the reported values of electrosynthesis of NH₃ to the knowledge. The introduction of W makes the Co atom surface electron deficient, which can enhance the adsorption of NO_x⁻ and mitigate the excessive bonding of hydroxyl radicals (OH^*) generated during nitrite (NO₂^*) hydrogenation, thereby reducing the energy barrier of the potential-determining step. More interestingly, a scale-up reaction system is established, achieving an NH₃ yield rate of 4.771 g h⁻¹ and successfully converting the NH₃ in solution into solid NH₄Cl. The aforementioned progress significantly enhances the facilitation of NH₃ electrosynthesis industrialization.     

3D Printed Sodium-Ion Batteries via Ternary Anode Design Affording Hybrid Ion Storage Mechanism

Sodium-ion batteries (SIB), as one of the most appealing grid-scale energy storage devices, have to deal with the trade-off between the capacity output and rate performance. Utilizing 3D-printed (3DP) anode materials with hybrid sodium storage mechanism and elevated mass loading is promising yet poorly explored. Herein, the design of a prototype ternary composite is reported, MoS₂@Bi/N-doped carbon, as a sodium storage candidate to achieve high reversible capacity (604 mAh g⁻¹ at 0.1 A g⁻¹ with an initial output of 709 mAh g⁻¹) and outstanding rate capability (169.6 mAh g⁻¹ at 15 A g⁻¹), outperforming the state-of-the-art reports. This is realized by delicate structural and interfacial engineering of the composite anode, markedly synergizing the conversion-typed MoS₂, alloy-typed Bi, and adsorption-typed N-doped carbon. Theoretical simulations and operando instrumental analysis elaborate the reasons of the boosted electrochemical performance. Encouragingly, a fully 3DP SIB affording an areal mass loading of up to 11.7 mg cm⁻² is demonstrated, retaining a capacity of 114 mAh g⁻¹ at 1.0 A g⁻¹. This work would facilitate the design of 3DP SIB devices with the employment of advanced electrodes harnessing hybrid ion storage features.     

Robust Hybrid Solid Electrolyte Interface Induced by Zn-Poor Electric Double Layer for A Highly Reversible Zinc Anode

Aqueous Zn-ion batteries (AZIBs) show great potential in new energy storage devices due to low cost, inherent safety, and environmental friendliness. However, the severe dendrites and side reactions on the anode greatly constrain their practical application. Herein, a novel colloidal electrolyte composed of ZnSO₄ and sodium carboxymethyl cellulose (CMC-Na) has been developed for inhibiting dendrite growth on Zn anode. Molecular dynamics (MD) simulation confirms that CMC-Na alters the electric double layer (EDL) structure of Zn anode surface to reduce the content of water and SO₄²⁻ and inhibit side reactions. More importantly, an organic/inorganic hybrid solid electrolyte interface (SEI) layer is in situ constructed during the cycling, which enables ultrastable Zn plating/stripping (> 2000 h) under high current density (5 mA cm⁻², 5 mAh cm⁻²) and high coulombic efficiency (99.8%) for more than 1000 cycles. Meanwhile, zinc-ion hybrid capacitors (ZIHCs) with the colloidal electrolyte exhibit a favorable capacitance retention of 97% after 15000 cycles at the current density of 2 A g⁻¹. Even at a high current density of 5 A g⁻¹, it still has a capacitance retention of 96% after 30000 cycles. This study presents a novel electrolyte strategy for the formation of ultrastable electrode-electrolyte interfaces in AZIBs.     

Construction of Stable Li2O-Rich Solid Electrolyte Interphase for Practical PEO-Based Li-Metal Batteries

Polyethylene oxide (PEO)-based solid polymer electrolytes (SPE) have garnered recognition as highly promising candidates for advanced lithium-metal batteries. However, the practical application of PEO-based SPE is hindered by its low critical current density (CCD) resulting from undesired dendrite growth. In this study, a PEO-based SPE that exhibits an ultra-high CCD (4 mA cm⁻²) is presented and enhanced lithium ionic conductivity through the incorporation of small amounts of P₂S₅ (PS). The crystalline Li₂O-rich and P/S-containing solid electrolyte interphase (SEI) is revealed by cryo-electron microscope (cryo-EM) and Time of flight secondary ion mass spectrometry (TOF-SIMS), which inhibits dendrite growth and adverse reactions between SPE and reductive lithium, thus offering a spherical growth behavior for dendrite-free lithium metal anode. Consequently, utilizing the PS-integrated SPE, a Li-Li symmetric cell demonstrates reduced resistance during operation, enabling stable cycles exceeding 200 hours at 0.5 mA cm⁻² and 0.5 mAh cm⁻², a stringent test condition for PEO-based electrolytes. Moreover, a Li/SPE/LiFePO₄ (LFP) pouch cell exhibits 80% capacity retention after 100 cycles with 50 µm Li and 30 µm PEO electrolyte, showcasing its potential for practical applications.     

Toward a Reversible Mn4+/Mn2+ Redox Reaction and Dendrite‐Free Zn Anode in Near‐Neutral Aqueous Zn/MnO2 Batteries via Salt Anion Chemistry

Rechargeable aqueous Zn/MnO₂ batteries are very attractive large‐scale energy storage technologies, but still suffer from limited cycle life and low capacity. Here the novel adoption of a near‐neutral acetate‐based electrolyte (pH ≈ 6) is presented to promote the two‐electron Mn⁴⁺/Mn²⁺ redox reaction and simultaneously enable a stable Zn anode. The acetate anion triggers a highly reversible MnO₂/Mn²⁺ reaction, which ensures high capacity and avoids the issue of structural collapse of MnO₂. Meanwhile, the anode‐friendly electrolyte enables a dendrite‐free Zn anode with outstanding stability and high plating/stripping Coulombic efficiency (99.8%). Hence, a high capacity of 556 mA h g^?1, a lifetime of 4000 cycles without decay, and excellent rate capability up to 70 mA cm^?2 are demonstated in this new near‐neutral aqueous Zn/MnO₂ battery by simply manipulating the salt anion in the electrolyte. The acetate anion not only modifies the surface properties of MnO₂ cathode but also creates a highly compatible environment for the Zn anode. This work provides a new opportunity for developing high‐performance Zn/MnO₂ and other aqueous batteries based on the salt anion chemistry.     

Interrelation Between External Pressure,SEI Structure,and Electrodeposit Morphology in an Anode-Free Lithium Metal Battery

The interrelation is explored between external pressure (0.1, 1, and 10 MPa), solid electrolyte interphase (SEI) structure/morphology, and lithium metal plating/stripping behavior. To simulate anode-free lithium metal batteries (AF-LMBs) analysis is performed on “empty” Cu current collectors in standard carbonate electrolyte. Lower pressure promotes organic-rich SEI and macroscopically heterogeneous, filament-like Li electrodeposits interspersed with pores. Higher pressure promotes inorganic F-rich SEI with more uniform and denser Li film. A “seeding layer” of lithiated pristine graphene (pG@Cu) favors an anion-derived F-rich SEI and promotes uniform metal electrodeposition, enabling extended electrochemical stability at a lower pressure. State-of-the-art electrochemical performance is achieved at 1MPa: pG-enabled half-cell is stable after 300 h (50 cycles) at 1 mA cm⁻² rate −3 mAh cm⁻² capacity (17.5 µm plated/stripped), with cycling Coulombic efficiency (CE) of 99.8%. AF-LMB cells with high mass loading NMC622 cathode (21 mg cm⁻²) undergo 200 cycles with a CE of 99.4% at C/5-charge and C/2-discharge (1C = 178 mAh g⁻¹). Density functional theory (DFT) highlights the differences in the adsorption energy of solvated-Li⁺ onto various crystal planes of Cu (100), (110), and (111), versus lithiated/delithiated (0001) graphene, giving insight regarding the role of support surface energetics in promoting SEI heterogeneity.     

Gradient-Structured and Robust Solid Electrolyte Interphase In Situ Formed by Hydrated Eutectic Electrolytes for High-Performance Zinc Metal Batteries

The mechanically and electrochemically stable and ionically conducting solid electrolyte interphase (SEI) is important for the stabilization of metal anodes. Since SEIs are originally absent in aqueous zinc metal batteries (AZMBs), it is very challenging to suppress water-induced side reactions and dendrite growth of Zn metal anodes (ZMAs). Herein, a gradient-structured and robust solid gradient SEI, consisting of B,O-inner and F,O-exterior layer, in situ formed by hydrated eutectic electrolyte for the homogeneous and reversible Zn deposition, is demonstrated. Moreover, the molar ratio of acetamide to Zn salt is modulated to prohibit the water activity and the hydrolysis of BF₄⁻ as well as to achieve high ionic conductivity owing to the regulation of the solvation sheath of Zn²⁺. Consequently, the eutectic electrolyte allows Zn||Zn symmetric cells to achieve a cycling lifespan of over 4400 h at 0.5 mA cm⁻² as well as Zn||PANI full cells to deliver a high capacity retention of 73.2% over 4000 cycles at 1 A g⁻¹ and to demonstrate the stable operation at low temperatures. This work provides the rational design for the hydrated eutectic electrolyte and the corresponding gradient SEIs for dendrite-free and stable Zn anodes even under harsh conditions.     

A Low-Cost Al(OH)3-Modified Fire-Retardant and Shuttle-Limiting Separator for Safe and Stable Lithium–Sulfur Batteries

Lithium–sulfur battery (LSB) possesses high theoretical energy density, but its poor cycling stability and safety issues significantly restrict progress in practical applications. Herein, a low-cost and simple Al(OH)₃-based modification of commercial separator, which renders the battery outstanding fire-retardant and stable cycling, is reported. The modification is carried out by a simple blade coating of an ultrathin composite layer, mainly consisting of Al(OH)₃ nanoparticles and conductive carbon, on the cathode side of the separator. The Al(OH)₃ shows strong chemical absorption ability toward Lewis-based polysulfides and outstanding fire retardance through a self-decomposition mechanism under high heat, while the conductive carbon material acts as a top current collector to prevent dead polysulfide. LSB using the Al(OH)₃-modified separator shows an extremely low average capacity decade per cycle during 1000 cycles at 2 C (0.029%, 1 C = 1600 mA g⁻¹). The pouch cell exhibiting high energy density (426 Wh kg⁻¹) can also steadily cycle for more than 100 cycles with high capacity retention (70.2% at 0.1 C). The effectiveness and accessibility of this Al(OH)₃ modification strategy will hasten the practical application progress of LSBs.     

In Situ Active Site Refreshing of Electro-Catalytic Materials for Ultra-Durable Hydrogen Evolution at Elevated Current Density

Enhancing the durability of catalysts is of critical significance to industrialize green hydrogen production. Herein, a novel active site in situ refreshing strategy is proposed and demonstrated to fabricate highly active and ultra-durable hydrogen evolution reaction (HER) electro-catalytic material by HER activation. Briefly, a composite catalytic material is synthesized, which features Ni(PO₃)₂ active sites being embedded inside the amorphous Mo compound matrix (named NiMoO-P). The Mo compound matrix undergoes gradual dissolution during HER followed by a dynamic equilibrium between the dissolution and deposition of the amorphous matrix. This process promotes the continuous exposure of insoluble Ni(PO₃)₂ and Ni₂P partially converted from Ni (PO₃) ₂ in situ on the surface during HER activation. Thus, activated catalyst exhibits excellent HER performance featuring an extremely high current density of 1500 mA cm⁻² at a rather low overpotential of 340 mV, and more attractively, an ultra-long durability for hydrogen evolution for at least 1000 h at an industrial-applicable current density of 900 mA cm⁻². The mechanisms for the especially high HER performance are attributed to the exposure and continuous refreshing of Ni(PO₃)₂ and the in situ formed Ni₂P during the HER process based on the DFT calculations and quasi-in situ Raman spectroscopic monitoring.