Controlled Hydrothermal Growth and Li⁺ Storage Performance of 1D VO_x Nanobelts with Variable Vanadium Valence

One-dimensional (1D) vanadium oxide nanobelts (VOx NBs) with variable V valence, which include V3O7·H2O NBs, VO2 (B) NBs and V2O5 NBs, were prepared by a simple hydrothermal treatment under a controllable reductive environment and a following calcination process. Electrochemical measurements showed that all these VOx NBs can be adopted as promising cathode active materials for lithium ion batteries (LIBs). The Li+ storage mechanism, charge transfer property at the solid/electrolyte interface and Li+ diffusion characteristics for these as-synthesized 1D VOx NBs were systematically analyzed and compared with each other. The results indicated that V2O5 NBs could deliver a relatively higher specific discharge capacity (213.3 mAh/g after 50 cycles at 100 mA/g) and median discharge voltage (~2.68–2.71 V vs. Li/Li+) during their working potential range when compared to other VOx NBs. This is mainly due to the high V valence state and good crystallinity of V2O5 NBs, which are beneficial to the large Li+ insertion capacity and long-term cyclic stability. In addition, the as-prepared VO2 (B) NBs had only one predominant discharge plateau at the working potential window so that it can easily output a stable voltage and power in practical LIB applications. This work can provide useful references for the selection and easy synthesis of nanoscaled 1D vanadium-based cathode materials