The research group of Professor Dong Quanfeng and the research group of Associate Professor Gong Lei of Xiamen University have made new progress in the research of solution phase catalysts for lithium air batteries

Professor Dong Quanfeng's research group and Associate Professor Gong Lei's research group of School of chemistry and chemical engineering of Xiamen University have made important progress in the aspect of solution phase catalyst of lithium air battery Relevant research results are published in chem (DOI: 10.1016/j.chempr.2018.08.029 ）。
Lithium air batteries use oxygen in the air and lithium metal as positive and negative active materials, with high energy density However, this system can not achieve commercial application, some of the key problems have not been solved Because the positive active material is gas, the electrochemical reaction involves gas-liquid-solid three-phase interface, and the electrode process is very complex Compared with other secondary batteries, the air electrode needs to consider the structural and catalytic factors It is necessary to not only improve the kinetic retardation of oxygen electrochemical reaction, but also consider the residence space of discharge products Professor Dong Quanfeng's research group carried out the research on solid-phase surface electrocatalysis of air electrode in the early stage, and combined with the problems of electrode structure, constructed a bionic open structure electrode that is conducive to oxygen reaction (adv energy mater., 2018, 8, 1800089; energy energy energy SCI., 2012, 5, 9765 – 9768; ACS catalyst., 2018, 8, 7983-7990) This work focuses on the study of liquid-phase catalysis, designs and synthesizes a ruthenium bipyridine complex (rupc) with high solubility in organic electrolyte, which can be used as the solution phase catalyst of lithium air battery The solution phase catalyst has the following functions: (1) the solution phase catalyst can move freely and form a good solid / liquid contact interface with lithium peroxide, so as to effectively improve the interface between lithium peroxide and catalyst; (2) in the process of discharge, its ruthenium gold center can interact with LiO2 species and induce LiO2 Dissolution can promote the reaction mechanism of solution phase, promote the expansion and growth of lithium peroxide, improve the electrochemical passivation of the electrode surface by LiO2, and improve the discharge capacity; (3) the catalyst can form relatively stable and less reactive intermediate product (rupc (lio2-3dmso)) with LiO2, significantly inhibit the occurrence of side reactions, and greatly improve the reversibility of lithium air battery; (4 ）In the process of charging, due to the interaction between ruthenium metal center and LiO2 species, lithium peroxide is first decomposed by one electron delionization Compared with the traditional two electron direct decomposition, the catalyst provides a more reversible and thermodynamic reaction path, which greatly reduces the charging overpotential Finally, the lithium air battery with the solution phase catalyst can obtain larger discharge capacity, longer cycle performance, lower charge over potential and fewer side effects The research work is mainly completed by Lin Xiaodong (first author), a 2015 i-chem direct doctoral student of School of chemistry and chemical engineering of Xiamen University, under the guidance of Professor Dong Quanfeng, Associate Professor Zheng Mingsen and Associate Professor Gong Lei The theoretical calculation is completed by Associate Professor Yuan Ruming (co first author) Cao Yong, Ding Xiaobing, Cai senrong and Han Bowen Wait for the students to participate in part of the work Professor Zhou Zhiyou and Dr Hong Yuhao gave great help and support in electrochemical differential mass spectrometry In addition, thanks to Professor Fu Gang's discussion and suggestions on theoretical calculation, Professor Eric Meggers's discussion on the synthesis of complexes, Professor Wu Qihui of Quanzhou Normal University and Dr Gu Yu of School of chemistry and chemical engineering of Xiamen University in X The help of X-ray photoelectron spectroscopy, the help of Mr Yu Lajia in electron paramagnetic resonance experiment, the help of Dr Tao Dandan in ultraviolet visible spectrum test and the discussion of Dr Wang Tao in cyclic voltammetry This work was supported by the major basic research plan of the Ministry of science and Technology (project approval No.: 2015cb251102), the National Natural Science Foundation (project approval No.: 21673196, 21621091, 21703186, 21773192) and the special funds for basic research business expenses of Central Universities (project approval No.: 20720150042, 20720150043).