Ultrathin Na_1.1V₃O_7.9 Nanobelts with Superior Performance as Cathode Materials for Lithium-Ion\nBatteries

Abstract

The Na_1.1V₃O_7.9 nanobelts have\nbeen synthesized by a facile and scalable hydrothermal reaction with\nsubsequent calcinations. The morphologies and the crystallinity of\nthe nanobelts are largely determined by the calcination temperatures.\nUltrathin nanobelts with a thickness around 20 nm can be obtained,\nand the TEM reveals that the nanobelts are composed of many stacked\nthinner belts. When evaluated as a cathode material for lithium batteries,\nthe Na_1.1V₃O_7.9 nanobelts exhibit\nhigh specific capacity, good rate capability, and superior long-term\ncyclic 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\nthe current density of 1500 mA g^–1. As demonstrated\nby the ex situ XRD results, the Na_1.1V₃O_7.9 nanobelts have very good structural stability upon cycling.\nThe superior electrochemical performances can be attributed to the\nultra-thin nanobelts and the good structural stability of the Na_1.1V₃O_7.9 nanobelts.