Fabrication of nickel oxide-titanium dioxide/reduced graphene oxide nanocomposites for developing asymmetric supercapacitor

Nickel oxide-titanium dioxide/reduced graphene oxide (NiOTiO2/rGO) nanocomposites were synthesized for the first time using a simple solvothermal method for asymmetric supercapacitor applications. Crystalline NiO and TiO2 nanoparticles were dispersed uniformly on different ratios of rGO multilayers. The specific capacitance was enhanced significantly with an increase in the ratio of rGO. The electrochemical performance of the prepared composites was evaluated in 1.0 M KOH solution. The NTG10 composite showed the highest specific capacitance among all the samples, reaching 793.6 F g-1 at a current density of 5 A g-1 with capacity retention of 89.37% of its initial specific capacitance over 5000 cycles. The suggested electrode achieved a maximum energy density of 33.4 Wh Kg-1 at a power density of 1377 W Kg-1. This enhanced storage performance is attributed to the synergistic combination of NiO, TiO2, and rGO materials which offers superior electrical conductivity, and pseudocapacitive charge-storage mechanisms. The results indicate that NiOTiO2/rGO nanocomposite is a promising electrode material for supercapacitor applications.