Chemically synthesized mesoporous nickel cobaltite electrodes of different morphologies for high-performance asymmetric supercapacitors

A facile, inexpensive, and template-free strategy has been investigated for the synthesis of nickel cobaltite (NiCo2O4; NCO) for different morphologies on conducting nickel foam using two different complexing agents' ammonia solution (AMM) and hexamethyltetrammine (HMT) and investigated for supercapacitor applications. The nickel cobaltite exhibits a mesoporous structure with pore diameters of 16 and 19 nm and provides a high specific surface area of 150, and 100 m2 center dot g- 1 for NCO-AMM and NCO-AMM, respectively. The NCO-HMT elec-trode exhibit higher specific capacities (2195.8 C center dot g-1/2744.8 F g-1 at 4 A.g- 1) than the NCO-AMM electrode (1579.7 C center dot g-1/ 1974.6 F g-1 at 4 A. g-1) with high capacity retention ( 86 %). Excellent cyclic stabilities of 95 and 97 % are obtained from NCO-AMM and NCO-HMT electrodes over 10,000 cycles. A fabricated ASC coin cell (NCO-HMT//rGO) enables a high operation potential window (1.6 V), and an excellent energy density of 60 Wh center dot kg- 1 with a power density of 5500 W center dot kg-1. The NCO-HMT//rGO also exhibits outstanding cyclic stability of 90 % over 10,000 charge-discharge cycles at 10 A center dot g-1 current density. This facile synthesis approach provides a superior strategy for producing mesoporous nanomaterials for high-performance ASC.

Automated summary

A facile, inexpensive, and template-free strategy was used to synthesize nickel cobaltite with high specific surface area and specific capacities for supercapacitor applications. The study showed excellent cyclic stability and high performance of the synthesized materials.