Promoting Homogeneous Interfacial Li⁺ Migration by Using a Facile N₂ Plasma Strategy for All‐Solid‐State Lithium‐Metal Batteries

Abstract Hybrid solid electrolytes (HSEs) with satisfactory ionic conductivities, good flexibilities, and ideal interface compatibilities are crucial for the development of all‐solid‐state lithium‐metal batteries. However, Li dendrites and sluggish interfacial Li⁺ transfer dynamics between the Li metal and HSEs restrict practical applications. Herein, a facile strategy is proposed to promote homogeneous interfacial Li⁺ migration by modifying HSEs by using nitrogen plasma. N₂ plasma not only decreases the crystallinity and glass transition temperature of HSE but also in‐situ generates an ultra‐stable and conductive Li₃N layer on the HSE surface. This conductive layer promotes interfacial Li⁺ migration and favorable wettability, thus effectively improving Li⁺ transfer dynamics and homogeneous deposition. Therefore, a HSE modified by N₂ plasma for 10 s exhibits a low interfacial impedance of 26.5 Ω cm⁻² and a high Li⁺ conductivity of 7.35 × 10⁻⁵ S cm⁻¹ at 30 °C. Moreover, a symmetric Li|HSE|Li battery exhibits a stable plating/stripping capability without Li dendrite growth at a current density of 0.1 mA cm⁻² during continuous operation over 1000 h. In addition, an all‐solid‐state Li|HSE|LiFePO₄ battery exhibits an initial specific capacity of 145.0 mAh g⁻¹ at 1 C with a high capacity retention of 92.4% (134.0 mAh g⁻¹) after 140 cycles.