High-rate and durable sulfide-based all-solid-state lithium battery with in situ Li2O buffering

Sulfide electrolytes (SEs)-based all-solid-state lithium batteries (ASSLBs) are advantageous over traditional lithium-ion batteries (LIBs) because of high energy density and safety. Unfortunately, the commercialization of SEs-based ASSLBs is presently hindered by interfacial instability between SEs and active materials, sluggish dynamics and poor cycling performance. Here we report, for the first time, a stable and conductive Li2O buffering coating for Ni-rich LiNi0.8Co0.1Mn0.1O2 (NCM811) in ASSLBs using SEs of Li6PS5Cl via a facile one-step sintering. We show using judiciously combined computation and experiment that Li2O buffering improves the stability of NCM811 and significantly boosts transfer of Li+. Via tuning the thickness of the Li2O buffer, we demonstrate the high initial discharge capacity of 189.66 mAh g − 1 (0.1C) and rate capability of 61.71 mAh g − 1 (3C), together with outstanding long-term cycling performance of ∼ 2600 cycles at 1C with capacity retention of 81.47%, and Coulombic efficiency of 99.9%. We conclude that conductive Li2O buffering can be used to obviate interfacial instability between SEs and active materials and to boost dynamics and cycling performance. Findings will be of immediate benefit to a range of researchers in design for high-performance ASSLBs for practical application and commercialization.