Interfacial Super-Assembled Porous CeO2/C Frameworks Featuring Efficient and Sensitive Decomposing Li2O2 for Smart Li-O2 Batteries

The Li-O-2 battery (LOB) represents a promising candidate for future electric vehicles owing to its outstanding energy density. However, the practical application of LOB cells is largely blocked by the poor cycling performance of cathode materials. Herein, an ultralong 440-cycle life of an LOB cell is achieved using CeO2 nanocubes super-assembled on an inverse opal carbon matrix as the cathode material without any additives. CeO2 is proved to be effective for the complete and sensitive decomposition of loosely stacked Li2O2 films during the oxygen evolution reaction process and full accommodation of volume changes caused by the fast growth of Li2O2 films during the oxygen reduction reaction process. The super-assembled porous CeO2/C frameworks satisfy critical requirements including controlled size, morphology, high Ce3+/Ce4+ ratio, and efficient volume change accommodation, which dramatically increase the cycle life of LOB cell to 440 cycles. This study reveals the design strategy for high performance CeO2 catalyst cathodes for LOB cells and the generation mechanisms of Li2O2 films during the discharge process by using density functional theory calculations, showing new avenues for improving the future smart design of CeO2-based cathode catalysts for Li-O-2 batteries.