Abstract
Metal phosphide materials have drawn much attention due to their high supercapacitive activity. In this work, MOF-derived carbon coated Cu3P with Ni doping (Cu3P/C-Ni) is prepared by using a Cu-MOF-based precursor with trace nickel ions as a precursor along with a high-temperature reduction and low-temperature phosphorization treatment. By controlling the content of doped nickel ions, the best effect of improving the specific capacity of the Cu3P-based material as a supercapacitor electrode material is achieved. The prepared Cu3P/C-Ni electrode with a Ni content of 6% (Cu3P/C-6% Ni) delivers a high specific capacitance (283.8 C g(-1) at 1 A g(-1)), excellent rate performance (98 C g(-1) at 20 A g(-1)) and cycle stability (60% of the initial capacity after 10 000 cycles at 10 A g(-1)). Remarkably, an asymmetric supercapacitor (ASC) is assembled with active carbon as the anode. The Cu3P/C-6% Ni//AC ASC presents a high energy density of 15.2 W h kg(-1) at 800.1 W kg(-1), giving enhanced capacitive performance. This synthesis method provides a promising strategy for exploring Cu3P-based electrodes for supercapacitors with high performance and low costs.