Operando electrochemical pressiometry probing interfacial evolution of electrodeposited thin lithium metal anodes for all-solid-state batteries

Abstract

All-solid-state Li metal batteries with ultimate energy density require stabilization at the Li/solid electrolyte interfaces. Further, the use of conventional thick (hundreds of μm) Li metal anodes (LMAs) hinders an impartial evaluation of full cells. In this study, interfacial evolution is compared for thin LMAs (∼ 10 μm thick) prepared by a scalable electrodeposition, with varying protective In/LixIn layer formed via electroless plating. The positive effects of the In/LixIn layer are confirmed for both Li/Li6PS5Cl/Li symmetric cells and LiNi0.70Co0.15Mn0.15O2/Li6PS5Cl/Li full cells. Complementary analysis including electrochemical, ex situ X-ray photoelectron spectroscopy, operando electrochemical pressiometry, and cross-sectional scanning electron microscopy measurements discloses complex Li/Li6PS5Cl interfacial evolutions affected by the In/LixIn coatings, that is, suppressed side reactions and penetrating Li growth. Importantly, a new indicator from operando electrochemical pressiometry analysis, the capacity-normalized pressure change difference Δ(ΔPQ) successfully predicts the dendritic growth of Li during cycling of LiNi0.70Co0.15Mn0.15O2/Li full cell.