Electrolyte-Impregnated Mesoporous Hollow Microreactor to Supplement an Inner Reaction Pathway for Boosting the Cyclability of Li-CO 2 Batteries.

Li-CO 2 batteries that integrate energy storage with greenhouse gas fixation have received a great deal of attention in the pursuit of carbon neutrality. However, cyclic accumulation of the insulative and insoluble Li 2 CO 3 on the cathode surface severely restrains the battery cyclability, especially under a high depth of discharge/charge. Herein, we design and fabricate a microreactor-type catalyst by embedding Ru nanoparticles into the shells of mesoporous hollow carbon spheres. We show that both the hollow cavity and mesoporous shell are indispensable for concertedly furnishing a high activity to catalyze reversible Li 2 CO 3 formation/decomposition. This unique structure ensures that the Ru sites masked by exterior Li 2 CO 3 deposits during charging can resume the redox process of discharge by working with the prestored electrolyte to establish an inner reaction path. The thus fabricated Li-CO 2 batteries demonstrate remarkable cyclability of 1085 cycles under 0.5 Ah g -1 and 326 cycles under 2 Ah g -1 at 1 A g -1 , outshining most of the literature reports. This study highlights a smart catalyst design to boost the reversibility and cyclability of Li-CO 2 batteries through an "in & out" strategy.