Fundamental Understanding of Nonaqueous and Hybrid Na–CO₂ Batteries: Challenges and Perspectives

Abstract Alkali metal–CO₂ batteries, which combine CO₂ recycling with energy conversion and storage, are a promising way to address the energy crisis and global warming. Unfortunately, the limited cycle life, poor reversibility, and low energy efficiency of these batteries have hindered their commercialization. Li–CO₂ battery systems have been intensively researched in these aspects over the past few years, however, the exploration of Na–CO₂ batteries is still in its infancy. To improve the development of Na–CO₂ batteries, one must have a full picture of the chemistry and electrochemistry controlling the operation of Na–CO₂ batteries and a full understanding of the correlation between cell configurations and functionality therein. Here, recent advances in CO₂ chemical and electrochemical mechanisms on nonaqueous Na–CO₂ batteries and hybrid Na–CO₂ batteries (including O₂‐involved Na–O₂/CO₂ batteries) are reviewed in‐depth and comprehensively. Following this, the primary issues and challenges in various battery components are identified, and the design strategies for the interfacial structure of Na anodes, electrolyte properties, and cathode materials are explored, along with the correlations between cell configurations, functional materials, and comprehensive performances are established. Finally, the prospects and directions for rationally constructing Na–CO₂ battery materials are foreseen.