All-solid-state Li metal batteries (ASLMBs) are the key to achieving high energy densities; however, studies on practically relevant pouch-type cells remain scarce. A critical challenge lies in integrating thin solid electrolyte films, particularly under the high pressures required for cell assembly, which has been largely overlooked. Here, we reveal the inherent incompatibility of conventional sulfide solid electrolyte films with Li metal during pouch cell assembly. To address this challenge, we introduce a simple yet effective post-engineering strategy that modifies the chemical interactions between Li₆PS₅Cl and nitrile butadiene rubber binders, significantly enhancing the mechanical robustness and Li metal compatibility, even under 450 MPa isostatic pressing. Complementary experimental analyses and finite element method simulations identify the underlying enhancement mechanism as the improvement of mechanical properties, which increases the interfacial friction. Leveraging these advancements, we successfully assemble LiNi_0.70Co_0.15Mn||Li ASLMB pouch cells without any interlayers through single-step pressurization, achieving remarkable performance at 3 MPa, with 400-cycle stability at 60°C and reliable operation at 30°C. Finally, we demonstrate a proof-of-concept bipolar-stacked ASLMB pouch cell, showcasing its scalability and practicality. These findings establish a new benchmark for ASLMBs and provide key design principles for advancing practical high-energy all-solid-state technologies.

Understanding the composition and properties of the first cycle irreversible capacity in Li-rich layered oxides is crucial for stimulating the full energy potential of these promising high-energy-density cathodes.

GNM electrodes exhibit superior electrochemical properties.

ABSTRACT Research into halide solid electrolytes has intensified due to their high ionic conductivity, oxidation stability and ductility, yet their close‐packed anion frameworks offer limited structural tunability, hindering further enhancement of bulk Li + conduction. Here, we demonstrate a universal bulk oxygen incorporation strategy for halide solid electrolytes, using WO 2 Cl 2 to enable controlled introduction of oxygen into diverse Li x MCl 6 (M = Zr, Y, Er, and In) lattices, effectively enhancing Li + conduction. Complementary structural, spatial, and vibrational analyses, including synchrotron X‐ray techniques, depth‐resolved spectroscopy, and Raman measurements, confirm oxygen incorporation via the [WO 2 Cl 4 ] 2− polyhedral unit, validating the structural integrity of the modified halides. First‐principles calculations reveal that the anchored oxygen flattens the Li + migration energy landscape by diversifying Li sites and weakening Li–Cl interactions, accounting for the observed conductivity enhancement. In addition, the alleviation of the thermodynamic driving force for hydrolysis improves air and moisture stability, and the enhancement in ionic conductivity leads to improved electrochemical performance. These oxygen‐anchored oxychlorides offer lattice‐level regulation principles that underpin conventional halide design, ensuring both practicality and broad applicability.

Understanding the complex structural and chemical factors that influence ionic conduction mechanisms is paramount for developing advanced inorganic superionic conductors in all-solid-state batteries, particularly halide solid electrolytes with excellent electrochemical oxidative stability and mechanical sinterability. Herein, contrasting ionic conduction behaviors in I^- and Br^- substituted Li₂ZrCl₆ are revealed by combining experimental structural analyses and theoretical calculations. The inter-slab distance along the c-axis, which varies with the anion substitution and M2-M3 site disorder, is a key factor for opening the ab-plane conduction and facilitating the overall Li⁺ conduction. Increased M3 site occupancy generally leads to contracted inter-slab distance. The substantial increase in Li⁺ conductivity upon I substitution (from 0.40 to 0.91 mS cm^-1) originates from a sufficiently expanded lattice volume owing to its large ionic radii (I^- = 2.20 Å), particularly inter-slab distance that facilitates the ab intra-plane Li⁺ conduction, which also benefits from decreased M2-M3 disorder. In contrast, Br (Br^- = 1.96 Å) substitution results in insufficiently expanded Li⁺ channels, which, exacerbated by increased M2-M3 disorder, leads to degradation in Li⁺ conductivity. Implementing I^- substituted Li₂ZrCl₆ resulted in superior electrochemical performance in LiCoO₂||Li-In cells compared to those with an unsubstituted catholyte.

This review paper explores the emerging field of conversion cathode materials, which hold significant promises for advancing the performance of lithium-ion (LIBs) and lithium-sulfur batteries (LSBs). Traditional cathode materials of LIBs, such as lithium cobalt oxide, have reached their limits in terms of energy density and capacity, driving the search for alternatives that can meet the increasing demands of modern technology, including electric vehicles and renewable energy systems. Conversion cathodes operate through a mechanism involving complete redox reactions, transforming into different phases, which enables the storage of more lithium ions and results in higher theoretical capacities compared to conventional intercalation materials. This study examines various conversion materials, including metal oxides, sulfides, and fluorides, highlighting their potential to significantly enhance energy density. Despite their advantages, conversion cathodes face numerous challenges, such as poor conductivity, significant volume changes during cycling, and issues with reversibility and stability. This review discusses current nanoengineering strategies employed to address these challenges, including nano structuring, composite formulation, and electrolyte optimization. By assessing recent research and developments in conversion cathode technology, this paper aims to provide a comprehensive overview of their potential to revolutionize lithium-ion batteries and contribute to the future of energy storage solutions.

All-solid-state Li metal batteries (ASLMBs) are the key to achieving high energy densities; however, studies on practically relevant pouch-type cells remain scarce. A critical challenge lies in integrating thin solid electrolyte films, particularly under the high pressures required for cell assembly, which has been largely overlooked. Here, we reveal the inherent incompatibility of conventional sulfide solid electrolyte films with Li metal during pouch cell assembly. To address this challenge, we introduce a simple yet effective post-engineering strategy that modifies the chemical interactions between Li₆PS₅Cl and nitrile butadiene rubber binders, significantly enhancing the mechanical robustness and Li metal compatibility, even under 450 MPa isostatic pressing. Complementary experimental analyses and finite element method simulations identify the underlying enhancement mechanism as the improvement of mechanical properties, which increases the interfacial friction. Leveraging these advancements, we successfully assemble LiNi_0.70Co_0.15Mn||Li ASLMB pouch cells without any interlayers through single-step pressurization, achieving remarkable performance at 3 MPa, with 400-cycle stability at 60°C and reliable operation at 30°C. Finally, we demonstrate a proof-of-concept bipolar-stacked ASLMB pouch cell, showcasing its scalability and practicality. These findings establish a new benchmark for ASLMBs and provide key design principles for advancing practical high-energy all-solid-state technologies.

Understanding the composition and properties of the first cycle irreversible capacity in Li-rich layered oxides is crucial for stimulating the full energy potential of these promising high-energy-density cathodes.

GNM electrodes exhibit superior electrochemical properties.