Suppresses dissolution and enhanced conductivity in core-shell VO${}_2$@Ni${}_3$N as a high-capacitance and improved cycling anode materials for supercapacitor

Vanadium dioxide, as one of superior pseudocapacitive electrode candidates in supercapacitors, suffers from the detrimental dissolution in aqueous electrolytes and poor intrinsic electronic conductivity. Herein, an ultrathin Ni${}_3$N shell is deposited on the VO${}_2$ surfaces (VO${}_2$@Ni${}_3$N) to inhibit the inevitable dissolution during charge/discharge processes. Meanwhile, the Ni${}_3$N coating layer also provides sufficient electron transport pathways for the rapid surface faradic reactions of VO${}_2$, promoting the electrochemical reaction kinetics. The designed VO${}_2$@Ni${}_3$N anode exhibits significant energy storage ability, especially at large current density (2058 F g${}^{-1}$ at 1 A g${}^{-1}$, 711 F g${}^{-1}$ at 7 A g${}^{-1}$), and the considerable cycling lifespans (capacitance retention of 91.3% after 5000 cycles). The asymmetric supercapacitor presents an energy density of 41.73 Wh kg${}^{-1}$ at a power density of 1176.7 W kg${}^{-1}$. This study may enlighten the design of advanced pseudocapacitive materials for practical electrochemical energy storage technologies. (© 2023 The Authors. Advanced Energy and Sustainability Research published by Wiley‐VCH GmbH)