Defective ZnCoNiP nanosheets derived from metal-organic-frameworks as electrodes for high-performance supercapacitors

Abstract

Transition metal phosphides are a promising electrode materials for supercapacitors because of their outstanding electrical conductivity and high electrochemical activity. In this work, Zn/Co metal organic framework (MOF) was used as a self-sacrificing precursor for hydrothermal and low-temperature phosphorylation to prepare zinc-cobalt-nickel phosphide composite. Due to the multi-metal synergistic effect of Zn, Co and Ni can promote efficient utilization of active substances, and the unique nanosheet-like structure, the obtained ZnCoNiP-D metal phosphide electrode shows a high capacity of 770.4 C g−1 at 1 A g−1, outstanding performance (466.7 C g−1 at 20 A g−1) and good capacity retention rate of 81.8 % after 5000 cycles. More meaningfully, the assembled HPC//ZnCoNiP-D asymmetric supercapacitor exhibits an energy density of 40.6 Wh kg−1 at 266.6 W kg−1 and retains 85 % of specific capacitance after 5000 cycles. The above excellent results show that the paper offers a novel method for the preparation of high-performance ternary metal phosphide supercapacitors using MOFs as self-sacrificing templates.