Multi-walled carbon nanotubes decorated CdO/Co₃O₄ hexagonal nanoplates: Unveiling their potential in hybrid supercapacitor

A simple synthesis process for hybrid transition metal oxides is a crucial way for their application in energy storage system. In this work, multi-walled carbon nanotubes (MWCNTs) decorated CdO/Co₃O₄ hexagonal like nanoplates are prepared by fast emerging co-precipitation process. Further, CdO/Co₃O₄/MWCNT composite is used for energy storage performance and, specific capacity of 214.5 mAh g⁻¹ is obtained at 1 A g⁻¹. The capacity of CdO/Co₃O₄/MWCNT is found to be higher from the capacities of CdO (40.25 mAh g⁻¹), Co₃O₄ (100.5 mAh g⁻¹) and CdO/Co₃O₄ (171.63 mAh g⁻¹). Further, hybrid supercapacitor (HSC) is designed by CdO/Co₃O₄/MWCNT (positive electrode) and activated carbon (AC) (negative electrode). The CdO/Co₃O₄/MWCNT//AC delivers the high energy density of 37 W h kg⁻¹ with the power density of 750 W kg⁻¹. In addition, to confirm the electronic applicability for portable appliances, four green color light-emitting diodes (LEDs), kitchen timer and toy motor fan are operated separately by two CdO/Co₃O₄/MWCNT//AC hybrid supercapacitor connected in series.