Facile preparation of an oxygen-functionalized carbon felt electrode to improve VO2+/VO2+ redox chemistry in vanadium redox flow batteries

Herein, a new method for the facile introduction of oxygen-containing functional groups on a carbon felt electrode in a short treatment time has been proposed for application in a vanadium redox flow batteries (VRFBs). Benzoyl peroxide (BPO) can produce free radicals by attacking the C=C bonds or C-H bonds of the carbon felt. The generated unstable free radicals allow further reactions with oxygen to yield oxygen containing functional groups on the surface of the carbon felt electrode. The electrochemical performance of the BPO-treated carbon felt electrode toward the VO2+/VO2+ redox reaction was superior to that of the pristine carbon felt electrode. Therefore, the VRFB cell employing the BPO-treated carbon felt electrode showed an outstanding energy efficiency of 75% at a current density of 100 mA cm(-2). This improvement is attributed to the well-known electrocatalytic effects of the oxygenfunctionalized surface properties of the BPO-treated carbon felt electrode. (C) 2021 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.