Highly Crystalline Layered VS2 Nanosheets for All-Solid-State Lithium Batteries with Enhanced Electrochemical Performances.

All-solid-state lithium batteries employing inorganic solid electrolytes have been regarded as an ultimate solution to safety issues because of their features of no leakage as well as incombustibility and they are expected to achieve higher energy densities owing to their simplified structure. Two-dimensional transition-metal dichalcogenides exhibit a great potential in energy storage devices because of their unique physical and chemical characteristics. In this work, 50 nm thick highly crystalline layered VS2 (hc-VS2) nanosheets are prepared by a solvothermal method, and their electrochemical performances are evaluated in Li/75% Li2S-24% P2S5-1% P2O5/Li10GeP2S12/hc-VS2 all-solid-state lithium batteries. At 50 mA g-1, hc-VS2 nanosheets show a high reversible capacity of 532.2 mAh g-1 after 30 cycles. Moreover, stable discharge capacities are maintained at 436.8 and 270.4 mAh g-1 at 100 and 500 mA g-1 after 100 cycles, respectively. The superior rate capability and cycling stability are ascribed to the better electronic conductivity and well-developed layered structure. In addition, the electrochemical reaction kinetics and capacity contributions were analyzed via cyclic voltammetry measurements at different scan rates.