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

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 capacitive performance for supercapacitors was achieved by varying the deposition time from 5 to 20 min. When the electrodeposition time was 15 min, an optimal performance 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 capacitive 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 indicates that the proposed electrodeposition synthesis process and the prepared NiCoP composites hold high potential for applications in the field of energy storage technology.