Dandelion-clock-inspired preparation of core-shell TiO2@MoS2 composites for high performance sodium ion storage

Abstract Sodium ion batteries (SIBs) have great potential to be next-generation energy storage devices because of abundant sodium sources and its low cost. To improve the performance of SIBs, electrode materials with high capacities and cycling stabilities are highly desirable. Herein, inspired by the structure of a dandelion clock, core-shell TiO2@MoS2 composites were prepared by growing MoS2 nanoflakes on TiO2 nanospheres via a facial solvothermal method. The electrochemically stable TiO2 nanospheric core which likes the receptacle in a dandelion clock provides a robust support for the radial growth of MoS2 nanosheets, which like the pappi in the dandelion clock. The dandelion-clock-like structure can effectively prevent the aggregation of the MoS2 nanosheets, providing increased active sites. Strong interface interaction between TiO2 and MoS2 as revealed by XPS and HRTEM analyses could significantly promote the electron transfer and maintain the structural integrity of the composites. When used as anode materials for SIBs, the TiO2@MoS2 composites exhibit remarkable improved rate and cycling performance. This work indicates that the consideration of the morphology and structure is the key for the rational design and preparation of high performance electrode materials.