Metal-Free Electron Donor-Acceptor Pair Enabled Long-Term Stability of Li-CO2 Battery.

ABSTRACT

The challenges of Lithium-carbon dioxide (Li-CO2) batteries for ensuring long-term cycling stability arise from the thermodynamically stable and electrically insulating discharge products (e.g., Li2CO3), which primarily rely on their interaction with the active materials. To achieve the optimized intermediates, the bifunctional electron donor-acceptor (D-A) pairs are proposed in cathode design to adjust such interactions in the case of B-O pairs. The inclusion of BC2O sites allows for the optimized redistribution of electrons via p-π conjugation. The as-obtained DO-AB pairs endow the enhanced interactions with Li+, CO2, and various intermediates, accompanied by the adjustable growth mode of Li2CO3. The shift from solvation-mediated mode into surface absorption mode in turn manipulates the morphology and decomposition kinetics of Li2CO3. Therefore, the corresponding Li-CO2 battery got twofold improved in both the capacity and reversibility. The cycling prolongs exceed 1300 h and well operates at a wide temperature range (20-50 °C) and different folding angles (0-180°). Such a strategy of introducing electron donor-acceptor pairs provides a distinct direction to optimize the lifetime of Li-CO2 battery from local structure regulation at the atomic scale, further inspiring in-depth understandings for developing electrochemical energy storage and carbon capture technologies.