[001] preferentially-oriented 2D tungsten disulfide nanosheets as anode materials for superior lithium storage

Abstract

Rechargeable lithium ion batteries (LIBs) have transformed portable electronics and will play a crucial role in transportation, such as electric vehicles. For higher energy storage in LIBs, two issues should be addressed, that is, the fundamental understanding of the chemistry taking place in LIBs and the discovery of new materials. Here we design and fabricate two-dimensional (2D) WS₂ nanosheets with preferential [001] orientation and perfect single crystalline structures. Being used as an anode for LIBs, the WS₂-nanosheet electrode exhibits a high specific capacity, good cycling performance and excellent rate capability. Considering the controversy in the lithium storage mechanism of WS₂, ex-situ X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS) analyses clearly verify that the recharge product (3.0 V vs. Li⁺/Li) of the WS₂ electrode after fully discharging to 0.01 V (vs. Li⁺/Li) tends to reverse to WS₂. More remarkably, the [001] preferentially-oriented 2D WS₂ nanosheets are also promising candidates for applications in photocatalysis, water splitting, and so forth.