Template and binder free 1D cobalt nickel hydrogen phosphate electrode materials for supercapacitor application

Abstract

Herein, we synthesized 1D bimetallic hydrogen phosphate [CoxNix(HPO4)] nanorods by using a simple and effective chemical bath deposition method for supercapacitor applications. The prepared CoxNix(HPO4) was analyzed by Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) pattern. The surface morphology was envisaged by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) methods. The porous nature and surface area of the materials were characterized by nitrogen sorption isotherm and a high specific surface area of 153 m2 g−1 was found to be for Co0.75Ni0.25(HPO4). The Co0.75Ni0.25(HPO4) displays a maximum specific capacity of 475 mA h g−1 at 1 A g−1 in a three-electrode configuration using 3 M KOH as the electrolyte. Co0.75Ni0.25(HPO4) exhibits almost 94.8% of its initial specific capacity over 5000 GCD cycles at 10 A g−1. Furthermore, the fabricated asymmetric supercapacitor (ASC) with Co0.75Ni0.25(HPO4) and activated carbon (AC) showed a high specific capacitance of 182.5F g−1 at 0.5 A g−1. The ASC device delivered a maximum energy density of 64.88 Wh kg−1 at a power density of 800 W kg−1.