An Approach to Preparing Ni–P with Different Phases for Use as Supercapacitor Electrode Materials

Herein, we describe a simple two‐step approach to prepare nickel phosphide with different phases, such as Ni 2 P and Ni 5 P 4 , to explain the influence of material microstructure and electrical conductivity on electrochemical performance. In this approach, we first prepared a Ni–P precursor through a ball milling process, then controlled the synthesis of either Ni 2 P or Ni 5 P 4 by the annealing method. The as‐prepared Ni 2 P and Ni 5 P 4 are investigated as supercapacitor electrode materials for potential energy storage applications. The Ni 2 P exhibits a high specific capacitance of 843.25 F g −1 , whereas the specific capacitance of Ni 5 P 4 is 801.5 F g −1 . Ni 2 P possesses better cycle stability and rate capability than Ni 5 P 4 . In addition, the Fe 2 O 3 //Ni 2 P supercapacitor displays a high energy density of 35.5 Wh kg −1 at a power density of 400 W kg −1 and long cycle stability with a specific capacitance retention rate of 96 % after 1000 cycles, whereas the Fe 2 O 3 //Ni 5 P 4 supercapacitor exhibits a high energy density of 29.8 Wh kg −1 at a power density of 400 W kg −1 and a specific capacitance retention rate of 86 % after 1000 cycles.