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All‐solid‐state Li‐metal battery (ASSLB) represents advantageous energy storage system for automotive applications. For ASSLB, inorganic solid electrolyte is essential in determining safety and cycling performance. However, significant challenges persist in practical construction of ASSLB with optimized electrolyte. Specifically, electrolyte's structural instability influencing its electrochemical performance remains critical issue within typical operating temperatures for ASSLB in electric vehicles. Herein, this challenge is fundamentally addressed by substituting trace amount of lithium with cadmium, which lacks crystal field stabilization energy. This strategy of atomic interaction modification has induced electrolyte's structural distortion and electronic alteration by deliberately introducing disorder at local lithium sites. Li symmetric cell with cadmium‐substituted antiperovskite solid electrolyte exhibits outstanding critical current density of 11.5 mA cm−2 (5.75 mAh cm−2) and excellent stability for 3000 h at 10.0 mA cm−2 (5.0 mAh cm−2). This study highlights explicit research direction for breakthrough of ASSLB, focusing on understanding how local distortion affects complex inorganic materials. [ABSTRACT FROM AUTHOR]

All‐solid‐state Li‐metal batteries (ASSLBs) are the most attractive next‐generation batteries due to intrinsic safety and high energy density. Particularly, composite solid electrolyte (CSE)‐based ASSLBs, highly compatible with conventional Li‐ion batteries, are nearing commercialization. However, the understanding of ASSLBs’ failure remains deficient, thereby considerably hindering their advancement. Herein, the unrecognized failing mode of ASSLBs, voltage noise failure (VNF), characterized by irregular charging voltage configuration, is identified using comprehensive techniques, including laser‐induced breakdown spectroscopy. The VNF originates from micro‐penetration of Li dendrites, which is demonstrated through direct observation of 3D Li concentration map in CSE. In this phenomenon, the transition metals, dissolved from the cathode, hop to the anode and serve as seeds for dendritic growth in VNF. Inspired by this mechanism and with the aid of DFT calculations, a transition metal scavenging layer is proposed using Prussian blue analogue at the cathode‐CSE interface. Consequently, ASSLBs with transition metal scavenging layer exhibit superior capacity (189 mAh g−1 at 0.5 C, NCM811) and stable cyclability (1200 cycles without failure). [ABSTRACT FROM AUTHOR]

Solid‐state batteries (SSBs) employing Li‐metal anodes (LMAs) show significant potential for overcoming the energy density limitations inherent in conventional Li‐ion batteries with graphite anodes. In the past decade, diverse approaches have tried to improve the cycling performance of SSBs, including chemical modifications of solid electrolytes (SEs) and designs of multifunctional interlayers. However, knowledge gaps regarding the physical characteristics of Li‐ion conducting inorganic SEs and the interfacial stability of LMAs are impeding advancements in battery technology. Herein, a practical strategy is developed to facilitate Li‐ion mobility and mitigate current constriction at the interfaces via manganese substitution into antiperovskite SEs, inspired by how liquid electrolyte additives modify the surface characteristics of LMAs. Due to the stable half‐filled 3d shell of manganese, the physically modified SE can achieve structural endurance and electrochemical compatibility with LMA. The Li symmetric cell employing this advanced SE demonstrates outstanding electrochemical performance at room temperature without external pressure. This cell configuration exhibits a high critical current density of 10.5 mA cm−2 and maintains its stable charge–discharge process over 4000 cycles at 10.0 mA cm−2. The findings here will advance the commercialization of SSBs by providing insights into the complicated solid‐solid interactions during battery operation. [ABSTRACT FROM AUTHOR]