Single-step wet-chemical fabrication of sheet-type electrodes from solid-electrolyte precursors for all-solid-state lithium-ion batteries

Abstract

All-solid-state lithium-ion batteries (ASLBs) employing sulfide solid electrolytes (SEs) have emerged as promising next-generation batteries for large-scale energy storage applications in terms of safety and high energy density. While slurry-based fabrication processes using polymeric binders and solvents are inevitable to produce sheet-type electrodes, these processes for ASLBs have been overlooked until now. In this work, we report the first scalable single-step fabrication of bendable sheet-type composite electrodes for ASLBs using a one-pot slurry prepared from SE precursors (Li₂S and P₂S₅), active materials (LiNi_0.6Co_0.2Mn_0.2O₂ or graphite), and polymeric binders (nitrile-butadiene rubber (NBR) or polyvinyl chloride (PVC)) via a wet-chemical route using tetrahydrofuran. At 30 °C, the LiNi_0.6Co_0.2Mn_0.2O₂ and graphite electrodes wet-tailored from SE precursors and NBR exhibit high capacities of 140 mA h g⁻¹ at 0.1C and 320 mA h g⁻¹ at 0.2C, respectively. Particularly, the rate capability of the graphite electrode in an all-solid-state cell is superior to that of a liquid electrolyte-based cell. Additionally, the effects of the size of the SE precursors and the polymeric binders on the electrochemical performance are investigated. Finally, the excellent electrochemical performance of LiNi_0.6Co_0.2Mn_0.2O₂/graphite ASLBs assembled using the as-single-step-fabricated electrodes are also demonstrated not only at 30 °C but also at 100 °C.