Anhui Provincial Key Laboratory of Advanced Functional Materials and Devices;
School of Materials Science and Engineering;
Hefei University of Technology;
Hefei 230009;
China;
Key Laboratory of Materials for Energy Conversion Chinese Academy of Sciences;
Department of Materials Science and Engineering;
University of Scienceand Technology of China;
Hefei 230026;
China;
Vanadium pentoxide; Cathode; Free-standing electrode; Rechargeable sodium batteries;