Electrochemistry of metal-CO2 batteries: Opportunities and challenges

As a greenhouse gas and common pollutant, atmospheric CO2 is a pressing concern toward climate change caused by increased CO2 emissions driven by fossil fuel-based energy production. There is an urgent need for a solution to capture and convert CO2 as part of the effort to combat climate change. Metal-CO2 batteries represent a promising technology to capture and recycle carbon dioxide while serving as an energy storage solution for a renewable energy network. Though metal-CO2 research is very active, the technology is still in its very early stages. Therefore, more fundamental mechanisms need to be understood before a practical metal-CO2 battery configuration is realized. Metal-CO2 battery research delves into a large variety of materials and chemistries depending on the anode material, which can be lithium, sodium, zinc, aluminum, magnesium, or potassium. This review summarizes the fundamental electrochemistry and mechanisms of different metal-CO2 batteries. The material selection, design considerations, mechanisms of electrochemical charge and discharge, and catalyzed behaviors of metal-CO2 batteries are also comprehensively examined. We hope understanding the underlying electrochemistry of metal-CO2 batteries will promise the development of the battery technologies that are applicable to a broad range of both carbon capture and energy storage applications.