All-solid-state lithium-ion batteries with TiS₂ nanosheets and sulphide solid electrolytes

Bulk-type all-solid-state lithium-ion batteries (ASLBs) using sulphide solid electrolytes (SEs) are considered as one of the promising alternative batteries because of their ultimate safety and scalable fabrication. However, they suffer from poor ionic contacts between active materials and SEs. Herein, we report, for the first time, the excellent electrochemical performances of sulphide-SE-based bulk-type ASLBs employing TiS₂ nanosheets (TiS₂-NSs) prepared by scalable mechanochemical lithiation, followed by exfoliation in water under ultrasonication. The TiS₂-NS in all-solid-state cells exhibits an enhancement of reversible capacity which is attributed to the SE region in intimate contact with TiS₂-NSs. Importantly, an exceptionally superior rate capability of the TiS₂-NS compared to that of bulk TiS₂ and even ball-milled TiS₂, which is attributed to the ultrathin 2D structure (with short Li-ion diffusion length and intimate contacts between the TiS₂-NS and SE) and high electronic conductivity, is highlighted.