A novel carbon film electrode for supercapacitor by deposition of precursor sol on the current collector, followed by carbonization and activation in situ

Abstract

This article describes the making of a carbon electrode, where the precursor sol is directly electrosprayed on the current collector. The gel was cured in situ, and the use of carbon fiber paper ensured sufficient adhesion for such processing. Prior to carbonization of resorcinol-formaldehyde (RF) gel, the solvent is removed by lyophilization, whereby the internal pore structure is least affected. The carbon pores are activated by heating the composite in a CO2 environment. The features of nanoporosity and the oxygen functionality in the film after CO2 activation are evident from bulk characterization, e.g., BET, FTIR, and XRD. The specific capacitance of such carbon film with aqueous KOH solution as electrolyte is found to be more than 500 F g−1 at current density of 1 A g−1. 99.12% of this capacitance is retained after 1000 charge-discharge cycles. The product quality is further analyzed with reference to the mode of solvent removal from the RF sol and the extent of CO2 exposure during activation.