Ultrathin Na1.1V3O7.9 Nanobelts with Superior Performance as Cathode Materials for Lithium-Ion Batteries

The Na1.1V3O7.9 nanobelts have been synthesized by a facile and scalable hydrothermal reaction with subsequent calcinations. The morphologies and the crystallinity of the nanobelts are largely determined by the calcination temperatures. Ultrathin nanobelts with a thickness around 20 nm can be obtained, and the TEM reveals that the nanobelts are composed of many stacked thinner belts. When evaluated as a cathode material for lithium batteries, the Na1.1V3O7.9 nanobelts exhibit high specific capacity, good rate capability, and superior long-term cyclic stability. A high specific capacity of 204 mA h g–1 can be delivered at the current density of 100 mA g–1. It shows excellent capacity retention of 95% after 200 cycles at the current density of 1500 mA g–1. As demonstrated by the ex situ XRD results, the Na1.1V3O7.9 nanobelts have very good structural stability upon cycling. The superior electrochemical performances can be attributed to the ultra-thin nanobelts and the good structural stability of the Na1.1V...