Electrochemical performance of binder-free Ni(OH)₂/RGO battery type electrode materials for supercapacitor

Ni(OH)₂/reduced graphene oxide (RGO) core-shell hybrid nanostructure has been synthesized employing a facile and inexpensive chemical-precipitation technique. The synthesized core-shell nanostructures, comprising Ni(OH)₂ at the core and RGO as shell, were then coated on commercially available Ni foam used as an electrode. Prepared Ni(OH)₂/RGO nanospheres were analyzed by Raman analysis for structural information. In the Raman spectrum, the peaks at 1323 and 1612 cm⁻¹ correspond to the D and G bands of RGO, respectively. The peaks at 468 and 335 cm⁻¹ depict the characteristic bands of Ni(OH)₂. The core-shell morphology of the hybrid was established from Transmission Electron Microscope (TEM) images. The lattice fringes are measured to be 0.33 nm for RGO layers and 0.22 nm for Ni(OH)₂ core, which correspond to (002) plane of RGO and (101) plane of Ni(OH)₂. For electrochemical studies, the as-prepared Ni(OH)2/RGO hybrid was used as a battery-type electrode in supercapacitor. The results indicate that the Ni(OH)₂/RGO core-shell hybrid nanostructure exhibits a maximum specific capacity of 513.8 Cg⁻¹ at 10 mV/s with a maximum energy density of 119.4 Whkg⁻¹ at 1250 Wkg⁻¹ power density.