Promoting Homogeneous Interfacial Li+ Migration by Using a Facile N2 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. N-2 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 N-2 plasma for 10 s exhibits a low interfacial impedance of 26.5 omega cm(-2) and a high Li+ conductivity of 7.35 x 10(-5) S cm(-1) at 30 degrees 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.

Automated summary

This study proposes a facile strategy to promote homogeneous interfacial Li+ migration by modifying hybrid solid electrolytes (HSEs) using nitrogen plasma. The modified HSEs exhibit an ultra-stable and conductive Li3N layer on the surface, which improves Li+ transfer dynamics and homogeneous deposition. Experimental results show that the HSE modified by nitrogen plasma has low interfacial impedance and high Li+ conductivity, demonstrating good stability and the ability to achieve electrode deposition and stripping without Li dendrite growth.