Template-free synthesis of ultra-large V2O5 nanosheets with exceptional small thickness for high-performance lithium-ion batteries

Abstract

Similar to graphene, transition metal oxide nanosheets have attracted a lot of attention recently owning to their unique structural advantages, and demonstrated promising chemical and physical properties for various applications. However, the synthesis of transition metal oxide nanosheets with controlled size and thickness remains a great challenge for both fundamental study and applications. The present work demonstrates a facile solvothermal synthesis of ultra-large (over 100μm) VO2(B) nanosheets with an exceptionally small thickness of only 2–5nm corresponding to 3–8 layers of (001) planes. It can be readily transferred into V2O5 with well retained nanosheet structures when calcined, which exhibit remarkable rate capability and great cycling stability. Specifically, the as-synthesized vanadium pentoxide nanosheets deliver a specific discharge capacity of 141mAhg−1 at a current density of 0.1Ag−1, which is 96% of its theoretical capacity (147mAhg−1) for one Li+ ion intercalation/removal per formular within a voltage window of 2.5–4V. Even at an extreme-high current density of 5Ag−1, it still can exhibit a high specific discharge capacity of 106mAhg−1. It is worthy to note that the V2O5 nanosheets electrode can retain 92.6% of the starting specific discharge capacity after 500 discharge/charge cycles at the current density of 1.5Ag−1.