ESR study of electrochemical behavior of carbon black

The electrochemical properties of a carbon black used as the electrode material of a capacitor have been investigated. The carbon-black electrode was prepared from Ketjen Black EC by blending with polymers such as Teflon and NBR. Carbon capacitors that consist of two carbon-black electrodes and electrolyte solution (LiClO₄) exhibited good charge-discharge cycles. The capacity was independent of the thickness of the carbon-black electrode. The cyclic voltammograms of the carbon electrode showed anodic and cathodic peaks at a sweep rate of 2.5 mV/s. The formation of radical sites in the carbon black in the charge process was proved by in situ ESR measurements. The intensity of the ESR signal increased with the extent of electrochemical reduction.