High-performance hybrid supercapacitor with electrochemically exfoliated graphene oxide incorporated NiCo2O4 in aqueous and non-aqueous electrolytes

Hydrothermal approach is employed to synthesize electrochemically exfoliated graphene oxide (EGO) integrated NiCo2O4 micro-flowers with nano petals. Specific capacity of 59 mAh g-1 (530 F g-1) is achieved by the optimized weight percentage of EGO in NiCo2O4 with long cyclic stability over 10,000 cycles. Detailed analysis on charge-storage properties of NiCo2O4-EGO composite reveals individual capacitive and diffusive contributions at various scan rates. An asymmetric supercapacitor device is fabricated with EGO incorporated NiCo2O4 composite material and commercial YP-50F carbon as positive and negative electrodes in 1 M TEABF4 acetonitrile organic electrolyte for the first time. The device delivers promising electrochemical performance with energy and power densities of 37.8 Wh kg-1 and 1350 W kg-1. Present work suggests an eco-friendly synthesis of EGO and provides a cost-effective facile approach for improving the overall electronic conductivity and cyclic stability of NiCo2O4 and other similar metal oxide materials for high-performance supercapacitors.