Construction of Heterostructure Pseudocapacitive Electrode VN/MnO _x on Carbon Sheet Synthesized by C ₃ N ₄ Self‐Sacrifice Method for Supercapacitors

Vanadium nitride (VN) is considered as a promising electrode for supercapacitors, however, its easy oxidation and dissolution limited application widely. We proposed to construct a heterostructure pseudocapacitive electrode, VN/MnOx, on a carbon sheet synthesized by C₃N₄ self-sacrifice method for supercapacitors. This method can avoid NH₃ using and at the same time produce carbon material. The manganese content can be adjusted to decrease the bandgap, resulting in conductivity improvements and fast electrochemical kinetic, then enhancing the electrochemical performance. The optimized C/VN/MnO_x can deliver a maximum specific capacitance of 424 F g^-1 at 0.5 A g^-1, higher than C/VN-700 (150 F g^-1). Further, the assembled Ni(OH)₂//C/VN/MnO_x-700-1 device also exhibits high energy density of 37.05 Wh kg^-1, with an excellent cycle life of 84% after 20,000 cycles, which will further promote the application of VN in supercapacitors. This work provides a new method of ammonia-free synthesis route and constructs a heterostructure pseudocapacitive electrode to achieve high specific capacitance, advancing the practical application of VN-based materials in high-performance supercapacitors.