Synthesis of Hierarchical Sisal-Like VO with Exposed Stable {001} Facets as Long Life Cathode Materials for Advanced Lithium-Ion Batteries.

Vanadium pentoxide (VO) is considered a promising cathode material for advanced lithium-ion batteries owing to its high specific capacity and low cost. However, the application of VO-based electrodes has been hindered because of their inferior conductivity, cycling stability, and power performance. Herein, hierarchical sisal-like VO microstructures consisting of primary one-dimensional (1D) nanobelts with [001] facets orientation growth and rich oxygen vacancies are synthesized through a facile hydrothermal process using polyoxyethylene-20-cetyl-ether as the surface control agent, followed by calcination. The primary 1D nanobelt shortens the transfer path of electrons and ions, and the stable {001} facets could reduce the side reaction at the interface of electrode/electrolyte, simultaneously. Moreover, the formation of low valence state vanadium would generate the oxygen vacancies to facilitate lithium-ion diffusion. As a result, the sisal-like VO manifests excellent electrochemical performances, including high specific capacity (297 mA h g at a current of 0.1 C) and robust cycling performance (capacity fading 0.06% per cycle). This work develops a controllable method to craft the hierarchical sisal-like VO microstructures with excellent high rate and long-term cyclic stability.