Facile Synthesis of Bimetal Nickel Cobalt Phosphate Nanostructures for High-Performance Hybrid Supercapacitors

Abstract Herein, bimetal nickel-cobalt phosphate (NiCoP) nanostructures coated on nickel foam (NF) were synthesized for hybrid supercapacitors by a facile one-step potentiostatic electrodeposition method. The optimization of the capacity performance for supercapacitors was achieved by varying the deposition time from 5 to 20 min. When the electrodeposition time was 15 min, the optimal performance of supercapacitors with the NiCoP/NF-2 was achieved. A specific capacity of 883 C·g-1 was recorded at a current density of 1 A·g-1, a best rate performance of 87% along with a highest coulombic efficiency of 100%, revealing good capacity performance and excellent reversibility. Furthermore, NiCoP/NF-2 was assessed as a positive electrode in a hybrid supercapacitor. Using activated carbon (AC) as a negative electrode, the assembled device exhibited an energy density of 54 Wh·kg-1 at a power density of 2.7 kW·kg-1 with a large working potential window of 0-1.8 V. After charging to 3.6 V for 19 s, two hybrid supercapacitor devices connected in series could light up a red LED for 191 s, which indicats the proposed electrodeposition synthesis process and the prepared NiCoP composites promising high potential of application in the field of energy storage technology.