A New Material Na0.45VOPO4•1.58H2O with an Orthorhombic Structure is Applied as Cathode Material for Sodium-ion Batteries

Abstract

A new material Na0.45VOPO4•1.58H2O with an orthorhombic structure is applied as cathode material for sodiumion batteries. In this paper, the electrochemical properties of this material which has been successfully synthesized by electrochemical oxidation of vanadyl ions in a phosphoric acid medium have been investigated using cyclic voltammetry, galvanostatic charge-discharge, and a long cycle term. A reversible capacity of ~ 90 mAh g - 1 at 0.1 C was determined between 2.5 and 3.8 V (versus Na+/ Na) with a high average potential of 3.4 V and good cyclability (initial Coulomb efficiency > 97% after 20 cycles).