Engineering porous electrodes for next-generation redox flow batteries: recent progress and opportunities

Redox flow batteries are a promising electrochemical technology for energy-intensive grid storage applications, but further cost reductions are needed for universal adoption. As porous electrodes are responsible for functions within the flow cell that impact charge transfer, ohmics, and mass transport, improvements in electrode materials and design may yield significant performance and economic benefits. This mini-review summarizes recent developments in the design and characterization of porous electrodes with a focus on understanding and controlling both the microstructure and surface chemistry, which broadly align with mass transport and reaction kinetics. Key opportunities and challenges in the science and engineering of these materials are also presented with the goal of engaging the broader community and accelerating progress towards chemistry-specific flow battery electrodes.