Metal-organic frameworks derived transition metal phosphide/carbon for high performance asymmetric supercapacitor

Abstract

Transition metal phosphides (TMPs) with high electrochemical activity have emerged as promising electrode materials for supercapacitors. Herein, we reported a facile strategy to fabricate porous hollow nanostructure cobalt zinc nickel phosphide/carbon (CoZnNiP/C) composite derived from Zn/Co zeolitic imidazolate frameworks (ZIF) as precursor by a solvothermal reaction and followed phosphorization. As for the optimized CoZnNiP/C-2 electrode, it delivers a high specific capacity of 760 C g−1 and good rate performance (603 C g−1 at 20 A g−1). The good performances come from the unique hollow structure with abundant active sites and rich internal nanoporous channels inside the shell, which can promote the diffusion of ions. Moreover, the assembled asymmetric supercapacitor using CoZnNiP/C-2 as positive electrode and hierarchical porous carbon (HPC) as negative electrode delivers a high energy density of 45.9 W h kg−1 and superior electrochemical stability.