Redox Mediator-Enhanced Performance and Generation of Singlet Oxygen in Li-CO2 Batteries

Rechargeable Li-CO2 batteries as a novel system developed in recent years directly use CO2 as the reactant, which enables deeper penetration of energy storage and CO2 utilization. The Li-CO2 battery system, however, is at an early stage, and many challenges remained to be overcome urgently, especially the problem of high over-potential during the charging process. Here, we report a redox mediator, phenoxathiin, to assist the decomposition of Li2CO3 during the charging process, which effectively reduces the over-potential and improves the cycling performance of the battery. Furthermore, we detect the presence of singlet oxygen during the oxidation of Li2CO3 by phenoxathiin, which reveals more of the underlying science of the reaction mechanism of the Li-CO2 battery.

Automated summary

Rechargeable Li-CO2 batteries directly using CO2 as the reactant have the potential for deeper energy storage penetration and CO2 utilization, but face challenges. The addition of a redox mediator phenoxathiin has been found to reduce over-potential during charging and provide insights into the reaction mechanism of the Li-CO2 battery.