Performances of Co²⁺-Substituted NiMoO₄ Nanorods in a Solid-State Hybrid Supercapacitor

A hydrothermal method was conducted to synthesize Ni (1−α) Co (α) MoO 4 (α = 0, 0.1, 0.3, and 0.5 M) nanorods, which were proven as excellent electrode materials in a hybrid supercapacitor. Their electrochemical properties were also dependent on the Ni/Co ratio as demonstrated by different electrochemical techniques. Ni 0.5 Co 0.5 MoO 4 (α = 0.5 M) offered specific capacity ( Q g ) = 354 Cg –1 @1 Ag –1, a remarkable specific capacity with a notable retention capacity of 92% after 8000 repeated cycles at 10 Ag –1 . Ni 0.5 Co 0.5 MoO 4 with a high surface area outperformed the mono-metallic (NiMoO 4 ) and bimetallic (Ni 0.9 Co 0.1 MoO 4 and Ni 0.7 Co 0.3 MoO 4 ) nanostructures. The hybrid supercapacitor (Ni 0.5 Co 0.5 MoO 4 //activated carbon) delivered a maximum Q cell of 53 Cg –1 at 1 Ag –1 with an energy density of 16.2 Wh kg –1 and power density of 725 W kg –1 .