Ultrathin WS2 nanosheets vertically embedded in a hollow mesoporous carbon framework - a triple-shell structure with enhanced lithium storage and electrocatalytic properties

Ultrathin WS2 nanosheets are vertically embedded in hollow mesoporous carbon spheres (HMCSs) to form unique hierarchical triple-shell (WS2-C-WS2) hollow nanospheres, i.e. HTSHNs WS2/C, via a facile and scalable hydrothermal method. The as-synthesized HTSHNs WS2/C nanocomposites are confirmed to have an expanded interlayer spacing of WS2 with chemical bonding between WS2 and HMCSs. The expanded WS2 interlayer spacing contributes to the enhancement of the kinetics of ion/electron transport and the improvement of the electrochemical performance of the HTSHNs WS2/C. As a result, the optimized HTSHNs WS2/C composites deliver a superior rate capability of 396 mA h g(-1) at 10 A g(-1), and stable cycling performance up to 1000 cycles, presenting a capacity of 784 and 442 mA h g(-1) at 1 and 5 A g(-1), respectively. Additionally, HTSHNs WS2/C provide abundant catalytically active sites for the enhancement of the electrocatalytic activity for the hydrogen evolution reaction (HER).