A Highly Reversible Long-Life Li-CO₂ Battery with a RuP₂ -Based Catalytic Cathode

Rechargeable Li-CO₂ batteries have attracted worldwide attention due to the capability of CO₂ capture and superhigh energy density. However, they still suffer from poor cycling performance and huge overpotential. Thus, it is essential to explore highly efficient catalysts to improve the electrochemical performance of Li-CO₂ batteries. Here, phytic acid (PA)-cross-linked ruthenium complexes and melamine are used as precursors to design and synthesize RuP₂ nanoparticles highly dispersed on N, P dual-doped carbon films (RuP₂ -NPCFs), and the obtained RuP₂ -NPCF is further applied as the catalytic cathode for Li-CO₂ batteries. RuP₂ nanoparticles that are uniformly deposited on the surface of NPCF show enhanced catalytic activity to decompose Li₂ CO₃ at low charge overpotential. In addition, the NPCF its with porous structure in RuP₂ -NPCF provides superior electrical conductivity, high electrochemical stability, and enough ion/electron and space for the reversible reaction in Li-CO₂ batteries. Hence, the RuP₂ -NPCF cathode delivers a superior reversible discharge capacity of 11951 mAh g^-1 , and achieves excellent cyclability for more than 200 cycles with low overpotentials (<1.3 V) at the fixed capacity of 1000 mAh g^-1 . This work paves a new way to design more effective catalysts for Li-CO₂ batteries.