Search

Li-CO2batteries 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 Li2CO3on 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 Li2CO3formation/decomposition. This unique structure ensures that the Ru sites masked by exterior Li2CO3deposits 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-CO2batteries demonstrate remarkable cyclability of 1085 cycles under 0.5 Ah g–1and 326 cycles under 2 Ah g–1at 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-CO2batteries through an “in & out” strategy.

Owing to their structural tunability for furnishing high catalytic activity and photoactivity, perovskite oxides are a class of promising materials for high-performance photocathode catalysts in a photoassisted lithium oxygen battery (LOB), which is still in its infancy. Herein, single-crystalline LaCoO3(LCO) is successfully synthesized through a microwave-assisted approach and selenylated to simultaneously introduce anionic doping and oxygen vacancies, boosting not only the electrocatalytic activity toward reversible Li2O2formation/decomposition, but also the photoactivity to further reduce the charge/discharge polarization. As a result, LOBs utilizing Se-doped LCO as the photocathode catalyst demonstrate a superior performance under illumination in all aspects of energy efficiency, specific capacity, and cycling stability, ranking among the best reported in the literature for perovskite oxides. The photoenhanced charge kinetics is found to be correlated with the accelerated Li2O2nucleation with lowered granule size, which is key to both the improved charge/discharge capacity and reversibility. The results underscore the tailoring of perovskite structure to aggrandize both the catalytic activity and photoactivity for concertedly promoting the kinetics of LOBs.

The high activation barrier and sluggish kinetics of Li2CO3decomposition impose a severe challenge on the development of a Li-CO2battery with high Coulombic efficiency. To tackle this issue, herein we devise a novel synthetic tactic by combining electrostatic assembly with in situpolycondensation to obtain a single-atomic Ru catalyst of high density up to ∼5 wt %. When deployed to the CO2cathode, the catalyst delivered an extraordinary capacity of 44.7 Ah g–1, an ultralow charge/discharge polarization of 0.97 V at 0.1 A g–1(1.90 V at 2 A g–1), and a long-term cycling stability up to 367 cycles at 1 Ah g–1(196 cycles at 2 Ah g–1), outshining most of the state-of-the-art CO2cathode catalysts reported today. Further through extensive in situand ex situelectroanalytical, spectroscopic, and microscopic characterizations, we attribute the superb battery performance mainly to the highly reversible Li2CO3formation/decomposition, facilitated by the homogenized and downsized Li2CO3nucleation and growth on account of the high density single-atomic Ru loading. This work not only offers a facile method to fabricate single-atom catalysts with high mass loading but also sheds light on promoting the reversible Li-CO2reaction by mediating product morphology.