Dual Design on Hierarchically Hollow MoTe 2 /C with Ion/Electron Channel Engineering for High-Performance Sodium Storage.

Transition-metal tellurides have been investigated as novel anode materials for application in sodium-ion batteries (SIBs) due to their rich active sites and unique and controllable layered nanostructures. However, the weak structural strength and inferior intercalation/deintercalation kinetics inhibit the development of transition-metal tellurides. In this work, MoTe ₂ /C composites with two different hollow nanostructures are designed and prepared. By adjustment of the precursor structure, MoTe ₂ /C-2 exhibits superior sodium-storage performance because of its uniquely hollow nanostructure with self-assembled 2D flexible nanosheets grown on the external surface. MoTe ₂ /C-2 delivers a higher specific capacity (276 mAh g ^-1 at 0.1 A g ^-1 after 300 cycles), much more than MoTe ₂ /C-1 (201 mAh g ^-1 at 0.1 A g ^-1 after 300 cycles), and exhibits a long-time cycling performance (131 mAh g ^-1 at 1 A g ^-1 after 2000 cycles). The excellent sodium-storage performance derived from the rational structure design is beneficial for shortening the ion paths, facilitating the sodiation/desodiation process, and reinforcing the intrinsic structural stability, thus boosting the reaction kinetics and prolonging the cycling life. Meanwhile, the assembled full-cell maintains 101 mAh g ^-1 at 0.1 A g ^-1 after 50 cycles and lights an electric watch. The findings provide several new views for preparation of more transition-metal tellurides with multi-ion/electron migration channel engineering.