Progress in Flow Battery Research and Development

TLDR

Rapid depletion of fossil fuels and rising energy demand have spurred research into renewables, electric vehicles, and especially electrochemical storage, with redox flow batteries emerging as the most promising technology for future smart grids and EV applications. The paper provides a panoramic overview of redox flow battery systems and their hybrid alternatives. The authors conduct a comprehensive analysis of redox flow battery technologies, evaluating technical, economic, and environmental aspects while outlining limitations, challenges, and future research directions. The review finds that all‑vanadium redox flow batteries dominate current research and show strong promise for stationary applications, while emerging hybrid redox fuel cells may enable refuelable electric vehicles.

Abstract

The past few decades have shown a rapid and continuous exhaustion of the available energy resources which may lead to serious energy global crises. Researchers have been focusing on developing new and renewable energy resources to meet the increasing fuel demand and reduce greenhouse gas emissions. A surge of research effort is also being directed towards replacing fossil fuel based vehicles with hybrid and electric alternatives. Energy storage is now seen as a critical element in future "smart grid and electric vehicle" applications. Electrochemical energy storage systems offer the best combination of efficiency, cost and flexibility, with redox flow battery systems currently leading the way in this aspect. In this work, a panoramic overview is presented for the various redox flow battery systems and their hybrid alternatives. Relevant published work is reported and critically discussed. A comprehensive study of the available technologies is conducted in terms of technical aspects as well as economic and environmental consequences. Some of the flow battery limitations and technical challenges are also discussed and a range of further research opportunities are presented. Of the flow battery technologies that have been investigated, the all-vanadium redox flow battery has received the most attention and has shown most promise in various pre-commercial to commercial stationary applications to date, while new developments in hybrid redox fuel cells are promising to lead the way for future applications in mechanically and electrically "refuelable" electric vehicles.