Construction of Hollow Cobalt–Nickel Phosphate Nanocages through a Controllable Etching Strategy for High Supercapacitor Performances

Abstract

Bimetal phosphates, especially those with hollow structures, have been recognized as promising materials for energy storage application. However, research on hollow bimetal phosphates is quite rare because of the difficulty in controlling the preparation process. In this work, through a shell-coating and then controllable etching process, a nonspherical hollow bimetal (Co/Ni) phosphate nanocage (named ZIF-67-LDH-CNP-110) is successfully constructed for the first time, to the best of our knowledge. When utilized as an electrode material for supercapacitor application, the as-prepared nanocages exhibit a high specific capacitance of 1616 F g–1 at 1 A g–1 and excellent ratio capability of remaining 80.32% of initial capacitance at a high current density of 10 A g–1. In addition, the as-fabricated ZIF-67-LDH–CNP-110//AC hybrid supercapacitor presents a remarkable energy density of 33.29 Wh kg–1 at a power density of 0.15 kW kg–1.