A dual-ion accepting vanadium carbide nanowire cathode integrated with carbon cloths for high cycling stability

Abstract

Herein, we report vanadium carbide (V₈C₇) nanowires (NWs) axially grown on carbon cloths (CCs) as a dual-ion accepting cathode for both lithium (LIBs) and sodium-ion batteries (SIBs). Using a facile hydrothermal method, we grew V₂O₃ NWs on CCs and subsequently reduced them to V₈C₇ by annealing with carbon sources under a H₂/Ar atmosphere. In striking contrast to V₂O₅ NW cathodes obtained by annealing under air, the V₈C₇ NWs exhibit outstanding cycling stability during 500 cycles, and good rate capability for both LIBs and SIBs. V₈C₇ NWs as cathode active materials for LIBs exhibited 203.9 mA h g⁻¹ specific capacity at 0.1 C after 500 cycles, 91.12% cycling retention and a coulombic efficiency of 99.84%. As cathodes in SIBs, the V₈C₇ NWs delivered 176.34 mA h g⁻¹ specific capacity at 0.1 C during 300 cycles. Their defect sites by removal of the oxygen framework in V₂O₃ NWs have a high surface area (183.27 m² g⁻¹) and the unique 1D NW structure highly mitigates the volume changes during charge and discharge showing a superior electrochemical performance. Compared to commercially available cathodes, V₈C₇ nanowires have very good cycling stability and enhanced electrical conductivity. Moreover, the synergistic effect with 3D CCs utilized here as a current collector provides a large number of cation-accessible active sites in conjunction with high electrical conductivity and chemical stability.