Characterization and performance evaluation of electrodeposition synthesized cobalt-nickel layered double hydroxide and composites for high-efficiency hybrid capacitor applications

Abstract

In this thesis, “Characterization and performance evaluation of electrodeposition synthesized cobalt-nickel layered double hydroxide and composites for high-efficiency hybrid capacitor applications”, an efficient binder-free electrodeposition process was used to prepare cobalt nickel layered double hydroxide and its composites. Cobalt nickel layered double hydroxide (CN-LDH) benefits from a unique 2D layered structure with large interlayer spacing for ion transport. However, it suffers from restacking of layers leading to low electrical conductivity. Sulphur reduced graphene oxide increases mechanical strength, electrical conductivity, and wettability, while Hausmannite, manganese cobaltite and chromite improves the redox active capability and ion diffusion to improve the electrochemical performance of CN-LDH. The asymmetric supercapacitors fabricated using CN-LDH composites as positive electrodes and activated carbon as negative electrodes, exhibited excellent specific energy and power ranging from 55.8 to 80.2 W h kg -1 and 515 to 1117.7 W kg -1 , respectively, in 2 M KOH electrolyte within a cell voltage of 1.65 V.