Electrochemical performance of vertically grown WS2 layers on TiNb2O7 nanostructures for lithium-ion battery anodes

A hierarchical assembly of hair-cuticle-like WS2 nanostructures grown epitaxially and distributed homogeneously on a TiNb2O7 nanofiber (NF) backbone (WS2@TiNb2O7 HNs) is fabricated without the use of conductive carbon networks. Cross-sectional transmission electron microscopy morphologies reveal the growth behavior of the (0 0 2) planes of the WS2 nanostructures on the boundaries of the TiNb2O7 NFs. The Li+ diffusion behavior throughout the discharge/charge process is characterized by the Li+ diffusion coefficients, which are measured by the galvanostatic intermittent titration technique. In situ X-ray diffraction results elucidate the structural changes in the (0 0 2) and (1 0 1) planes of WS2 during the lithiation and delithiation processes in the voltage range of 0.01-3.0 V vs. Li/Li+. Additionally, high lithium storage stabilities are obtained at high current densities (627 mAh g(-1) at 1 A g(-1) after 200 cycles and 344 mAh g(-1) at 5 A g(-1) after 300 cycles). The unique design of the fabricated hybrid structure effectively prevents agglomeration and mitigates volume expansion of WS2 during repeated cycling, thereby endowing it with a certain degree of structural integrity.