<span style="font-size:15.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">A Comparative Study on Electrochemical Behaviour of Co₃O₄and Co₃O₄-MWCNTs for Supercapacitors</span>

Abstract

Co₃O₄and Co₃O₄/MWCNTswere prepared by hydrothermal process under autogenous pressure in Teflon lined autoclave and calcined at 250⁰C. Both samples were characterized by PXRD, FT-IR, SEM-EDS, TEM & FT-Raman to evaluate their surface and bulk properties. The PXRD pattern of the materials indicated the formation of cubic phase of Co₃O₄. FT-IR results showed the presence of metal oxygen bond in the samples. The SEM and TEM images of the Co₃O₄/ MWCNTs indicated spherical and cubic aggregates of metal oxide particles (10-30 nm) decorated both on the surface and inside the tubes of carbon nanotubes. The characteristic Ig and Id (graphitic and defects) Raman bands indicated the retention of tubular structure of MWCNTs even after the deposition of Co₃O_4. The calcined Co₃O₄-MWCNTscomposites and Co₃O₄exhibited specific capacitance of 284 & 205 F/g at a sweep rate of 2mVs^-1 in 6M KOH by cyclic voltammetry. The psuedocapacitance performances of calcined Co₃O₄-MWCNTs were found to be better than Co₃O₄. Chronopotentiometric studies made for the materials at a current density of 500mA/g indicated 100% columbic efficiency at 2000^th cycle for Co₃O₄/ MWCNTs which is a better electrode material than Co₃O_4.