The research group of Professor Dong Quanfeng of Xiamen University has made important progress in the research of cathode materials for lithium air batteries

Professor Dong Quanfeng's research group of Xiamen University has made important progress in the research of positive materials for lithium air batteries The related research results "an open structured matrix as oxygen method with high catalytic activity and large Li 2O 2 communications for lithium air batteries" are published in adv energy matrix Doi: 10.1002/aenm.201800089 ) This work has set us a good example to resolve the difficulties troubleshooting the Li-O 2 battery The editorial department recommends the research results as a "video summary" on Wiley online platform Non aqueous lithium air (li-o2) battery mainly stores energy based on the generation and decomposition of Li 2O 2 Because it uses lithium metal as the negative electrode and oxygen in the air as the active material of the positive electrode, it has a very high theoretical energy density, about 10 times of the existing lithium-ion battery, which is considered as the so-called "ultimate" chemical power supply Although lithium air battery is a very attractive electrochemical energy storage system, there are still many difficulties to be overcome in order to realize its wide application For the key air electrode, there are three main problems: (1) the structure of the gas electrode Li 2O 2, an insoluble discharge product, is easy to block the air electrode and hinder the diffusion and further reaction of oxygen, so that its actual discharge capacity is far lower than the theoretical discharge capacity; (2) the dynamics of oxygen reaction The oxidation-reduction reaction of oxygen on the air electrode is slow, which leads to a large overpotential (usually greater than 1V) during the charging and discharging process; (3) interface problems The contact interface between the discharge product Li 2O 2 and the air electrode directly affects the charging process, so that Li 2O 2 can not be completely decomposed, resulting in the poor reversibility of the lithium air battery (source: School of chemistry and chemical engineering, Xiamen University) aiming at these problems, a sisal co 9s 8 material with open structure was designed and synthesized in this study, and it was used as the anode of lithium air battery for the first time It is found that the open structure not only provides plenty of storage space for reaction products, but also effectively avoids the blockage of air electrode by insoluble Li 2O 2 Moreover, the special open structure is conducive to the capture and release of oxygen, providing guarantee for efficient and rapid electrode reaction; secondly, CO 9s 8 has excellent catalytic activity, effectively improving the oxygen reaction kinetics, greatly improving the electrode reaction speed; finally, CO 9s 8 has good oxygen affinity, which can induce oxygen to be in CO 9s 8 The surface reaction of nanorods produces lithium peroxide, forming excellent Li 2O 2 / electrode contact interface, which is conducive to give full play to the catalytic efficiency of CO 9s 8 in the charging process and promote the complete decomposition of Li 2O 2 Therefore, the co 9s 8 air electrode solves the above three problems comprehensively, and the corresponding lithium air battery shows excellent electrochemical performance Under the current density of 50 Ma g-1, the discharge capacity of 6875 MAH g-1 can be obtained Under the condition of controlling the discharge capacity of 1000 MAH g-1, the charge discharge overpotential can be reduced to 0.57 V, which is superior to the oxide based catalyst reported so far In this paper, the reaction mechanism of Li 2O 2 is also proposed based on the experiment and theoretical calculation Under the guidance of Professor Dong Quanfeng and Associate Professor Zheng Mingsen, the research work was mainly completed by Lin Xiaodong (the first author), a 2015 level I Chem direct doctoral student of our institute, the theoretical calculation part was completed by Assistant Professor Yuan Ruming (the co first author), and the doctoral students Cai senrong, Jiang Youhong, Lei Jie, Liu Sangui, etc participated in part of the work Professor Liao Honggang and Professor Wu Qihui of Quanzhou Normal University provided active help and support in TEM and XPS respectively In addition, Professor Fu Gang's suggestions on theoretical calculation were discussed by Dr Chen Jiajia (University of Glasgow) and Dr Wang suheng (2015 i-chiem direct doctoral student) This work was supported by the major basic research plan of the Ministry of science and Technology (973 Plan, project approval No.: 2015cb251102), the National Natural Science Foundation of China (project approval No.: 21673196, 21621091, 21703186) and the special fund for basic scientific research business expenses of Central University (project approval No.: 20720150042) Corresponding author: Professor Dong Quanfeng