Ni3V2O8@3D Porous Graphitic Biogenic Carbon Composite Electrode Material for High Performance Supercapacitors

In this paper, a green, low-carbon, and high specific capacitance electrode material for supercapacitors was investigated and developed. A three-dimensional porous graphitic carbon (PGCHC) was prepared by using waste corn husk as raw material and activated by potassium ferrate (VI) (K₂FeO₄). The Ni₃V₂O₈@PGCHC composite was then prepared by in situ growth of Ni₃V₂O₈ via a hydrothermal method. The enlarged specific surface area of the PGCHC material (1788.2 m² g^–1) with the activated porous structure (1.5 nm) provides multiple active sites for the material. The composite material still has a three-dimensional carbon skeleton structure. These porous structures also create fast channels for ion diffusion. Moreover, the graphitic carbon structure greatly improves the electrical conductivity, resulting in excellent multiplicity and electrochemical properties. The specific capacitance of Ni₃V₂O₈@PGCHC exhibits 1179.1 F g^–1 when the current density is at 1 A g^–1. The ASC device prepared by combining a Ni₃V₂O₈@PGCHC positive electrode and PGCHC negative electrode can reach 73% capacity retention after 5,000 cycles, and the Coulombic efficiency is close to 100%. A high energy density of 57.3 Wh kg^–1 was demonstrated at a power density of 850 W kg^–1. The green and low-carbon production materials and excellent electrochemical properties of Ni₃V₂O₈@PGCHC are promising to be utilized in new energy facilities in the future.