Li–CO2 and Na–CO2 Batteries: Toward Greener and Sustainable Electrical Energy Storage

Metal–CO2 batteries, especially Li–CO2 and Na–CO2 batteries, offer a novel and attractive strategy for CO2 capture as well as energy conversion and storage with high specific energy densities. However, some scientific issues and challenges existing restrict their practical applications. Here, recent progress of crucial reaction mechanisms on cathodes in Li–CO2 and Na–CO2 batteries are summarized. The detailed reaction pathways can be modified by operation conditions, electrolyte compositions, and catalysts. Besides, specific discussions from aspects of catalyst design, stability of electrolytes, and anode protection are presented. Perspectives of several innovative directions are also put forward. This review provides an intensive understanding of Li–CO2 and Na–CO2 batteries and gives a useful guideline for the practical development of metal–CO2 batteries and even metal–air batteries. Li/Na–CO2 batteries provide a promising strategy for CO2 capture and energy supply. Recent progress of reaction mechanisms is summarized and aspects of catalyst design, stability of electrolytes, and anode protection are discussed. Furthermore, perspectives of several innovative directions are presented to inspire researchers and spur the practical development of metal–CO2 batteries.