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 Li 2 O buffering coating for Ni-rich LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NCM811) in ASSLBs using SEs of Li 6 PS 5 Cl via a facile one-step sintering. We show using judiciously combined computation and experiment that Li 2 O buffering improves the stability of NCM811 and significantly boosts transfer of Li + . Via tuning the thickness of the Li 2 O 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 Li 2 O 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.