Intrinsic pseudocapacitive enhancement of NiCo 2 O 4 /activated carbon composites for high-performance supercapacitors

The high electrical conductivity and capacitance of NiCo 2 O 4 have made it a promising electrode material for supercapacitors with advantages in rapid energy storage, long cycle life, and potential for flexible applications. Nickel Cobaltite Oxide (NiCo 2 O 4 ) nanoflakes were successfully synthesized by the sol-gel method. The composite Activated carbon was made from waste coconut shells. The X-Ray Diffraction (XRD) pattern matches with the standard values, the crystallite sizes were found to be 7 nm using the Debye Scherrer formula. FTIR reveals the molecular bond of (NiCo 2 O 4 ) NFs and their composites peak at 541 cm -1 and 552 cm -1 confirms the formation of NiCo 2 O 4 Metal oxides. From optical absorption studies, it is found that both NiCo 2 O 4 NFS and NiCo 2 O 4 /AC composites have maximum absorption throughout the UV region. The bandgap increases from 1.26 eV to 1.34 eV on adding AC composites to NiCo 2 O 4 NFs. Scanning Electron microscopy (SEM) shows the formation of NiCo 2 O 4 nanoflakes. The activated carbon has high surface area with micropores, confirmed by BET analysis. Cyclic Voltammetry (CV) analysis shows that NiCo 2 O 4 /AC composite has a more specific capacitance at low scan rate of 10 mV/s, which is more than NiCo 2 O 4 NFs. Both the samples recorded high specific capacitance values of 142 F g -1 and 192 F g -1 at the current density of 1 A/g using GCD. From this NiCo 2 O 4 /AC composites may be a highperforming capacitor with intrinsic pseudocapacitive behaviour compared to NiCo 2 O 4 NFs which has extrinsic pseudocapacitive behaviour.