A review of lithium-O2/CO2 and lithium-CO2 batteries: Advanced electrodes/materials/electrolytes and functional mechanisms

Rechargeable lithium-O-2/CO2 and lithium-CO2 batteries are the promising energy devices expected to be the next generation of lithium batteries with high energy densities. However, their unsatisfactory performance of crucial materials such as electrodes, catalysts and electrolytes are still the challenges hindering the technology's practical applications. To develop high-performance lithium-CO2 batteries, worldwide researchers have been focusing on exploring new electrode/electrolyte materials and the related technologies by developing novel synthesis methods and innovative assembling techniques, understanding degradation mechanisms, and creating mitigation strategies with particular emphasis on catalysts for CO2 reduction reaction and CO2 evolution reaction as well as their reaction products. In this paper, the state-of-the-art development in lithium-CO2 battery key materials, components and device assembling along with functional and degradation mechanisms and mitigation strategies are comprehensively reviewed. To facilitate further research and development of lithium-CO2 batteries toward practical applications, the existing challenges and several future research directions are discussed in this paper.