Stabilized 2-Electron Oxalate Mechanism Enabled by Oriented 3D Mo1.33C MXene/rGO Catalyst for Enhanced Reversibility in Flexible Li-CO2 Batteries

The incomplete decomposition of Li₂CO₃ significantly impacts the reversible performance of lithium-carbon dioxide (Li-CO₂) batteries. Current catalysts reported so far can promote the decomposition of Li₂CO₃ to a certain extent, but are far from sufficient, and the modulation of the discharge product to the more decomposable Li₂C₂O₄ is a promising solution. However, Li₂C₂O₄ exhibits insufficient stability for prolonged cycling processes. Herein, a Mo_1.33C@rGO aerogel (MGA), an all-integrated flexible cathode catalyst, is prepared for Li-CO₂ batteries, where an abundance of mobile electrons produced by the organized Mo vacancies strengthens the bonding between Mo atoms and the intermediate C₂O₄²⁻, thereby stabilizing it during prolonged cycling and preventing its disproportionation into Li₂CO₃. At the same time, the oriented 3D framework of MGA provides ordered active sites and well-organized electron and ion transport channels, reducing charge transfer resistance and facilitating the decomposition of Li₂C₂O₄ with a minimal overpotential of 0.46 V, extending the cycle lifespan to 330 cycles at a current density of 20 µA cm⁻². These results highlight MGA's potential as a catalyst for stabilizing intermediates and promoting Li₂C₂O₄ decomposition, offering a promising pathway for efficient, long-lasting, advanced Li-CO₂ batteries.