Thermal vapor sulfurization of Ti3C2TX MXene to TiS2/carbon nanosheet cathode for long-life and high-loading all-solid-state lithium batteries

Stable and fast operation of all-solid-state lithium batteries (ASSBs) depends on durable and sufficient interfacial contacts between electrode components, especially when the loading and content of electrode active materials are high. Here, we propose promoting ionic/electronic transportations and contacts in sulfide electrolyte-based ASSBs by using TiS2/carbon nanosheets (TiS2/C-s) with large area-to-thickness aspect ratios as the cathode, which are prepared by simple thermal vapor sulfurization of exfoliated Ti3C2Tx MXene. The elastic 2D structure of the TiS2/C-s material can substantially improve interfacial contact with the solid electrolyte, minimize the diffusion distance of lithium ions, and buffer volume/stress changes during cycling, thereby ensuring the electrochemo-mechanical stability and fast reaction kinetics of electrodes. Consequently, a 50 wt% TiS2/C-s cathode without any conductive carbon additives demonstrates a high discharge capacity (295 mAh g(-1)), long-term cyclic stability (94.7 and 74.7 % capacity retention after 250 cycles at 0.1 mA cm(-2) and after 2300 cycles at 1 mA cm(-2), respectively), and decent rate capability (126.0 mAh g(-1) at 3 mA cm(-2)). Moreover, stable cycling with a high areal capacity (5.95 mAh cm(-2)) can also be achieved.