Constructing nanosheets-self-supported structure of cobalt-doped nickel phosphide with high electrochemical performance

Abstract

Although nickel-based phosphides as a promising category of electrode materials in supercapacitors have high intrinsic electrical conductivity, they still present unsatisfied electrochemical performance and cycling life so far, which is mostly attributed to the low-surface area or inappropriate microstructure. Therefore, constructing a microstructure that meets the requirements of supercapacitors is the key for improving the performance of nickel-based phosphides. In this work, we prepared the cobalt ions-doped Ni2P with a nanosheets-self-supported nanostructure by phosphating its precursor of cobalt ions-doped nickel hydroxynitrate. Ascribed to appropriate microstructure and elevated electrical conductivity, the cobalt ions-doped Ni2P exhibits high electrochemical and cycling performance. The cobalt ions-doped Ni2P not only shows high specific capacity of 1150.0 C g[Formula: see text] at the low current density 2.5 A g[Formula: see text], but also exhibits excellent high-rate performance about the capacity retention of 53% at high current density of 49.1 A g1, attributed to its nanosheet morphology and elevated electrical conductivity. By virtue of the nanosheets-self-supported structure, the cobalt ions-doped Ni2P also shows high cycling performance on capacity retention of 81% for 10,000 charge-discharge cycles. The high performance of cobalt ions-doped Ni2P obtained from electrochemical measurement confirms its prospect as a candidate electrode material for advanced application in supercapacitors.