Synergetic Effect of Surface-Controlled and Diffusion-Controlled Charge Processes of NiP/CoP@NF for High Energy Density Supercapacitor

Since the rapidly increasing concerns about contamination of the environment and demand for energy storage systems, the development of high energy density supercapacitors has been essential. Although the commercial electrode for the supercapacitor has been carbon-based material, other transition metal-based electrode materials, which are pseudocapacitive or battery-like materials, have been researched by lots of academic or commercial groups due to the low energy density of carbon material. In this study, by combining the pseudocapacitive MOF-derived CoP material with the battery-like NiP material, high energy density NiP/CoP electrode material was fabricated. NiP/CoP@NF exhibited superior specific capacitance of 1154.4 F g^-1 at 1 A g^-1, exhibiting the mixed charging mechanism of both CoP and NiP materials. An asymmetric supercapacitor (ASC) showed a high energy density of 27.7 Wh kg^-1 at the power density of 800 W kg^-1 with cycle retention of 86.36% at 10000 cycles.