Suppresses Dissolution and Enhanced Conductivity in Core–Shell VO2@Ni3N 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 Ni3N shell is deposited on the VO2 surfaces (VO2@Ni3N) to inhibit the inevitable dissolution during charge/discharge processes. Meanwhile, the Ni3N coating layer also provides sufficient electron transport pathways for the rapid surface faradic reactions of VO2, promoting the electrochemical reaction kinetics. The designed VO2@Ni3N 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.