Active site synergy of the mixed-phase cobalt diselenides with slight lattice distortion for highly reversible and stable lithium oxygen batteries  

作　　者：Minglu Li Chaozhu Shu Anjun Hu Yu Yan Miao He Jianping Long 

机构地区：[1]College of Materials and Chemistry&Chemical Engineering,Chengdu University of Technology,Chengdu 610059,China [2]State Key Laboratory of Electronic Thin Films and Integrated Devices,University of Electronic Science and Technology of China,Chengdu 610054,China

出　　处：《Journal of Materials Science & Technology》2021年第33期159-170,共12页材料科学技术（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(No.21905033);Department of Science and Technology of Sichuan Province(No.2019YJ0503);State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization(No.2020P4FZG02A)。

摘　　要：Many non-precious metal-based catalysts with high intrinsic activity for catalytic reactions are prone to structural degradation in practical application,which leads to poor stability.In this work,we propose c-CoSe_(2)/o-CoSe_(2)as the oxygen electrode of lithium-oxygen batteries(LOBs)to improve its cycle stability.The heterogeneous interface inside c-CoSe_(2)/o-CoSe_(2)leads to an increase in the covalence bonds between Co and Se ions,which greatly enhances the robustness of the crystal lattice,thereby improving the stability of the catalyst.In addition,the strong interaction between the mixed phases is favorable for adjusting the electron density around the active sites and boosting oxygen electrode kinetics.Moreover,the epitaxial growth of o-CoSe_(2)on c-CoSe_(2)will cause abundant heterogeneous interfaces and slight lattice distortion along the interfaces,thereby providing sufficient catalytic reaction sites.The DFT calculation results show that the optimized adsorption of intermediates at the heterogeneous interface plays an important role in boosting oxygen electrode reactions and improving the electrochemical performance of LOBs.The experimental results show that LOBs with the c-CoSe_(2)/o-CoSe_(2)electrodes exhibit outstanding performance,including large specific capacity of about 23,878 m A h g^(-1),high coulombic efficiency of up to 93.66%,and excellent stability of over 176 cycles(1410 h).

关 键 词：Li-O_(2)battery Oxygen electrode Structure design Lattice distortion Jahn-Teller effect 

分 类 号：O643.36[理学—物理化学] TM911.41[理学—化学]