This study investigates the structural evolution and catalytic performance of cobalt (II) sulfide (CoSₓ) catalysts in Li-CO₂ batteries. Using X-ray absorption spectroscopy (XAS), the researchers analyze the reconstruction of CoSₓ (x = 8/9, 1.097, and 2) pre-catalysts during battery operation, identifying the local geometric ligand environment of cobalt. They find that the oxidation state of cobalt significantly affects battery performance. Complete oxidation of CoS₁.097 and Co₉S₈ leads to electrochemical performance deterioration, while oxidation of CoS₂ terminates with Co-S₄-O₂ motifs, enhancing catalytic activity. Density functional theory (DFT) calculations show that partial oxidation modulates the electronic structure and shifts the d-band center to higher energy, improving catalytic ability. The study reveals that CoS₂, with a Co-S₄-O₂ motif, exhibits high performance with an overpotential of 0.43 V after 400 h, while CoS₁.097 and Co₉S₈ cathodes have overpotentials exceeding 2 V after only 200 h. The findings provide insights into the structural evolution during cycling and the structure-activity relationship in Li-CO₂ batteries. The study highlights the importance of understanding the structural changes and active motifs in catalysts for developing efficient Li-CO₂ batteries. The results demonstrate that partial oxygen substitution in CoS₂ enhances its catalytic ability and energy efficiency, making it a promising candidate for Li-CO₂ batteries. The study also shows that the performance of CoS₂ is superior to other sulfides, with a long cycling life and stable performance. The research contributes to the development of high-performance, stable catalysts for Li-CO₂ batteries.This study investigates the structural evolution and catalytic performance of cobalt (II) sulfide (CoSₓ) catalysts in Li-CO₂ batteries. Using X-ray absorption spectroscopy (XAS), the researchers analyze the reconstruction of CoSₓ (x = 8/9, 1.097, and 2) pre-catalysts during battery operation, identifying the local geometric ligand environment of cobalt. They find that the oxidation state of cobalt significantly affects battery performance. Complete oxidation of CoS₁.097 and Co₉S₈ leads to electrochemical performance deterioration, while oxidation of CoS₂ terminates with Co-S₄-O₂ motifs, enhancing catalytic activity. Density functional theory (DFT) calculations show that partial oxidation modulates the electronic structure and shifts the d-band center to higher energy, improving catalytic ability. The study reveals that CoS₂, with a Co-S₄-O₂ motif, exhibits high performance with an overpotential of 0.43 V after 400 h, while CoS₁.097 and Co₉S₈ cathodes have overpotentials exceeding 2 V after only 200 h. The findings provide insights into the structural evolution during cycling and the structure-activity relationship in Li-CO₂ batteries. The study highlights the importance of understanding the structural changes and active motifs in catalysts for developing efficient Li-CO₂ batteries. The results demonstrate that partial oxygen substitution in CoS₂ enhances its catalytic ability and energy efficiency, making it a promising candidate for Li-CO₂ batteries. The study also shows that the performance of CoS₂ is superior to other sulfides, with a long cycling life and stable performance. The research contributes to the development of high-performance, stable catalysts for Li-CO₂ batteries.