Simple in situ synthesis of carbon-supported and nanosheet-assembled vanadium oxide for ultra-high rate anode and cathode materials of lithium ion batteries

Abstract

A simple and efficient precipitation method has been developed for the in situ synthesis of a two-dimensional vanadium oxide@carbon nanosheet (2D V₂O₅@C NS). The crystalline structure, morphology and electrochemical performance of the as-prepared material were characterized systematically. The results demonstrate that the thickness of nanosheet is about 50 nm, and a thin C shell is successfully coated in situ on the surface of the V₂O₅ NS core. Benefiting from the intrinsic increased conductivity of the 2D V₂O₅@C NS and its robust NS structure, when the as-synthesized material is used as an anode material, it exhibits large reversible discharge capacity (860 mA h g⁻¹ at 0.5 A g⁻¹), good cycling performance (a high capacity of 802 mA h g⁻¹ at 1.0 A g⁻¹ after 200 cycles) and an ultra-high rate capability (reversible capabilities of 705 mA h g⁻¹ at 2.0 A g⁻¹, and 554 mA h g⁻¹ at 3.0 A g⁻¹). As a cathode material, the material also shows superior rate performance (reversible capabilities of 189, 166, 147, 139, 132, and 126 mA h g⁻¹ at 0.1, 0.2, 0.5, 0.8, 1.0, and 1.2 A g⁻¹, respectively). This work demonstrates a novel method for preparing vanadium-based NS material for high-performance lithium ion batteries.