Promoting Homogeneous Interfacial Li + Migration by Using a Facile N 2 Plasma Strategy for All‐Solid‐State Lithium‐Metal Batteries

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.