Co3O4 nanoparticle-dotted hierarchical-assembled carbon nanosheet framework catalysts with the formation/decomposition mechanisms of Li2O2 for smart lithium-oxygen batteries

Li-O-2 batteries (LOBs) have been regarded as promising candidates for the next generation of electric vehicles owing to their excellent energy density. Nevertheless, the practical application of LOBs with a sensible cathode material has largely been blocked due to their low-activity catalysts and inefficient product evolution. Combining carbon and metal oxide is one of the most effective strategies to realize the high capacity and lower overpotential for boosting the Li-O-2 battery performance. Herein, cobalt oxide (Co3O4) nanoparticle-dotted hierarchical-assembled carbon nanosheet frameworks (Co3O4-HCNFs) were fabricated using a facile two-step carbonization-calcined route and applied as high-efficiency electrochemical catalysts for Li-O-2 batteries. Co3O4 has been proved to be effective for the full composition/decomposition of generated Li2O2 thin films during the oxygen reduction reaction process (ORR) and the oxygen evolution reaction process (OER). Furthermore, the cobalt oxide nanoparticle-dotted hierarchical-assembled carbon nanosheet frameworks satisfy the relevant requirements including controlled morphology and efficient volume change accommodation, which delivered a high-performance with a large specific capacity of 14 949 mA h g(-1) and superior cycling stability with 180 cycles. This study designs a smart strategy with high-performance Co3O4 cathodes for Li-O-2 batteries and the composition/decomposition mechanisms of Li2O2 films, showing a favorable method for recomposing the future design of Co3O4-based advanced energy materials.