Study the impact of MWCNTs and rGO on nickel cerium oxide electrode material for hybrid battery-supercapacitor device and hydrogen production

Rare earth based materials have gained significant attention owing to their outstanding electrical conductivity and energy storage properties. In this work, we investigate the structural and electrochemical behavior of nanostructures composed of nickel cerium oxide (NiCe₂O₄), carbon nanotubes (CNTs), and reduced graphene oxide (rGO). NiCe₂O₄ was synthesized through a hydrothermal approach, while rGO was prepared using a modified Hummer's method. The resulting NiCe₂O₄@CNT@rGO composite electrode exhibited specific capacity (Qs) of 1523.5C g⁻¹ from the CV and 1470.6C g⁻¹ from GCD. Furthermore, the estimated specific capacitance (Cs) was 2376 F g⁻¹ from CV and 2254 F g⁻¹ from GCD measurements. In addition, a hybrid supercapattery device was assembled using NiCe₂O₄@CNT@rGO and AC electrode. This device delivered Qs of 166.1 Cg⁻¹ from the CV and 154.8 Cg⁻¹ from the GCD. The hybrid device demonstrated an impressive energy density (Ed) of 76.4 Whkg⁻¹ along with a high-power density (Pd) of 1897 Wkg⁻¹. Moreover, the NiCe₂O₄@CNT@rGO//AC system maintained 86.9 % capacity retention and 94.6 % Coulombic efficiency after 5000 cycles. Additionally, the NiCe₂O₄@CNT@rGO nanocomposite electrode exhibited excellent hydrogen evolution reaction (HER) activity, delivering a low overpotential of 32 mV and a Tafel slope of 29 mV dec⁻¹. These earth abundant composite electrodes open up promising opportunities for the development of advanced high performance hybrid energy storage device.