Uncovering the Geometry Activity of Spinel Oxides in Li-CO<sub>2</sub> Battery Reactions
Yingqi Liu, Peng-Fei Shu, Mengtian Zhang, Biao Chen, Yanze Song, Bingyi Lu, Rui Mao, Qiong Peng, Guangmin Zhou, Hui–Ming Cheng
Abstract
Oxide catalysts are attractive in Li-CO 2 batteries for their activity and stability. However, discerning the active sites and contributing factors for battery reactions is still challenging due to the presence of passive spectator species. Herein, we use Co 3 O 4 to uncover the geometry-dependent activity and propose the key parameters that govern reactions in the Li-CO 2 batteries. We find that octahedral Co plays a dominant role in promoting battery reaction kinetics due to its strong interaction with reactants. In particular, we investigate the correlations between the d-orbital configurations in octahedral sites and CO 2 activity, where low e g filling facilitates CO 2 –catalyst bonding. Therefore, catalysts containing octahedral Co, especially Co 3 O 4, show high activity and durability with a low overpotential of 1.0 V and a cycling life of 600 h. Our study exemplifies the role of local electronic and geometry structures in catalysis, which provides insight into catalyst design in Li-CO 2 batteries.