Carbon materials in redox flow batteries: Challenges and opportunities

Abstract

Redox flow batteries are a hot topic for both scientists and engineers. The use of carbon electrodes is ubiquitous, and their surface modification is one of the key issues that stands in the way of commercialization breakthroughs. In this critical analysis of the representative literature, we offer readers a necessary interdisciplinary view of the challenges and opportunities for researchers in the fields of carbon surface chemistry, batteries, fuel cells and electrocatalysis on solid surfaces. Though focused on carbon electrode materials for the vanadium redox flow battery, we provide experimental and quantum chemical insights applicable to many established and emerging electrochemical energy conversion technologies. Given the current state of the art, considerable effort is spent addressing the controversial role of oxygen functional groups in the electrocatalytic activity of graphene-based electrodes.