A V₂O₅-nanosheets-coated hard carbon fiber fabric as high-performance anode for sodium ion battery

Hard carbon with high special capacity has been widely studied as anode for sodium ion batteries (SIBs). Its storage sodium performance still needs to be further improved. Herein, a composite electrode was synthesized through growing V₂O₅ nanosheet array on free-standing hard carbon fiber fabric by solvothermal reaction. The electrochemical properties of the composite electrode were significantly enhanced compared with pure hard carbon fiber electrode. The composite showed a specific capacity from 241 mA h g⁻¹ at 50 mA g⁻¹ to 77 mA h g⁻¹ at 1000 mA g⁻¹ and a good cycling ability of 184 mA h g⁻¹ after 100 cycles at 100 mA g⁻¹. Except good storage Na ability for V₂O₅ nannosheets, the improvement of electrochemical performances also benefited from and the synergistic effect from the ability of fast electron transfer of hard carbon and the toleration for Na⁺ insertion of V₂O₅ nanosheet array, as well as the inhibitory effect on solid electrolyte interface (SEI) of nanostructure. Additionally, the free-standing electrodes could also increase the energy and power density. This will push the promising hard carbon material used as SIBs anode in practical applications.