Electronic structure engineering of RuCo nanoalloys supported on nanoporous carbon for Li–O2 batteries

The significant challenge faced by Li–O2 batteries (LOBs) lies in their slow oxygen reduction and evolution kinetics, which greatly necessitates the development of highly active catalysts. Herein, we report a high-performance oxygen cathode (RuCo-NC) that is achieved by uniformly dispersing the nanoalloy of noble metal Ru and transition metal Co on the three-dimensional (3D) nanoporous carbon. Density functional theory (DFT) calculations reveal a prominent electron transfer process between Ru and Co, along with a substantial abundance of electron transfer sites on RuCo-NC. These characteristics contribute to a strong positive equilibrium effect on the formation and decomposition of Li2O2, which is crucial for LOBs. Furthermore, the calculated Gibbs free energy change during the oxygen reduction and evolution processes indicates that RuCo-NC exhibits the smallest overpotential compared to single metal catalysts. As a result, this RuCo-NC cathode enables the resulting LOB with a larger discharge specific capacity, lower overpotential for efficient oxygen reduction and evolution, and excellent cycling stability. This work introduces an effective method for fabricating nanoalloy catalysts with enhanced efficiency, promising advancements in energy applications.