Reversible and irreversible reaction mechanisms of Li-CO batteries

• Published in: Chemical science (Cambridge) 2024-03, Vol.15 (13), p.484-481
• Main Authors: Zhang, Xinxin, Wang, Yu, Li, Yafei
• Format: Article
• ISSN: 2041-6520; 2041-6539
• DOI: 10.1039/d4sc00383g

Li-CO 2 batteries are considered a versatile solution for CO 2 utilization. However, their development, including reversibility and efficiency, is impeded by an inadequate understanding of Li-CO 2 electrochemistry, particularly the decomposition of carbon and the generation of by-product O 2 . Here, using typical Ru(0001) (reversible) and Ir(111) (irreversible) as model catalysts and employing state-of-the-art first-principles calculations, the rechargeable/reversible reaction mechanisms of Li-CO 2 batteries are disclosed. We find that electrolyte, often neglected or oversimplified in Li-CO 2 modelling, plays an essential role in CO 2 activation and C-C coupling affects the generation pathways of discharge intermediates due to the sluggish kinetics. The results rationalize experimental observations, which are also examined by constant-potential modelling. Specifically, by exploring the kinetics of the charging process, we discover that the reversibility of Ru(0001) is attributed to its ability to suppress O-O coupling while co-oxidizing Li 2 CO 3 and carbon. In contrast, Li 2 CO 3 decomposition on Ir(111) preferentially produces O 2 , during which carbon can only be partially decomposed. These findings solve long-standing questions and highlight the necessity of describing the explicit solvent effect in modelling, which can promote further studies on Li-CO 2 batteries. We disclose the rechargeable/reversible reaction mechanisms of Li-CO 2 batteries by using state-of-the-art first-principles calculations.