Multi-role TiO2 layer coated carbon@few-layered MoS2 nanotubes for durable lithium storage

Abstract

The combination of transitional-metal dichalcogenides with rigid TiO2 has been proved to be an effective strategy to improve their structural stability but the poor long-term cycling stability at high current density still hinders their practical applications. In this paper, a smart structure consisting of multi-role TiO2 coated on carbon@few-layered MoS2 (CMT) nanotubes was synthesized to achieve superior long-term cycling performance. In this unique structure, the anatase/rutile TiO2 is explored as a coating layer of MoS2, which not only accommodates the volume change resulting from the phase transformation from S to Li2S but also alleviates the “shuttle effect” caused by the dissolution of long-chain lithium polysulfides. Moreover, the carbon nanotubes serve as a conductive backbone for MoS2 to improve the electron transport ability of electrode and the few-layered MoS2 nanosheets with expanded interlayers can shorten the lithium-ion pathway and improve the lithium-ion diffusion mobility. Benefitting from the synergetic effects of TiO2 layer, carbon and MoS2, when applied as anode of LIBs, the CMT demonstrates an extraordinary long-term cycling performance (528.5 mAh g−1 at 1000 mA g−1 and 455.2 mAh g−1 at 2000 mA g−1 after 1000 cycles), which outperforms most of the MoS2-TiO2 based anode materials reported before. This work should offer new perspectives into exploring high-performance MoS2-TiO2 based anode materials for efficient lithium storage.