Improved electrochemical performance of nickel cobaltite/ multi-walled carbon nanotube composite as a hybrid electrode for supercapacitors

Abstract

Metal oxide and carbon nanotubes (CNT) interactions are deep-seated to activate high energy storage ability in energy storage devices. In the present study, NiCo2O4/MWCNT composite is synthesized by the sonochemical method and employed as a hybrid electrode in supercapacitors. The NiCo2O4/MWCNT hybrid electrode delivers a specific capacitance of 418.1 F g−1 (or specific capacity 57.22 mAh g−1) at 2 A g−1 in 6 M KOH electrolyte, which is more than two and half times higher than pristine NiCo2O4. Furthermore, the hybrid electrode displays the high-rate capability (73.1% @10A g−1) and cycling stability (95.2% after 2000 charge-discharge cycles) owing to improved electrical conductivity, low charge transfer resistance, and the good synergistic effect that emerges due to complementary effect. These remarkable electrochemical properties suggest that NiCo2O4/MWCNT composite expected to be a note-worthy supercapacitor electrode material.