Adv. energy mater: team He Ping and Zhou Haoshen of Nanjing University published research results of solid-state lithium metal battery

The research team of He Ping and Zhou Haoshen from the school of modern engineering and Applied Sciences, Nanjing University has made new progress in the field of research on the stability of the negative electrode / electrolyte interface of solid-state lithium metal batteries Relevant research papers were published on advanced energy materials, an international famous journal in the field of energy, with the title of "germanium thin film protected lithium aluminum germanium PHOSPHORE for solid state Li batteries" (1) schematic diagram of sputtering germanium film on the surface of solid-state electrolyte; (2) schematic diagram of charge and discharge of solid-state lithium lithium symmetrical battery (source: adv energy mater.) lithium metal battery has been widely concerned because of its high specific energy At present, the liquid organic electrolyte used in lithium battery has potential safety problems, such as leakage, combustion and explosion In addition, the lithium dendrite of the negative electrode may pierce the electrolyte layer during the cycle of the lithium battery using lithium as the negative electrode, resulting in the short circuit of the battery, resulting in safety accidents such as combustion or explosion In order to solve this problem fundamentally, researchers use solid electrolyte as lithium-ion conductor Solid electrolyte has the advantages of high conductivity, wide electrochemical window and high mechanical strength The NASICON solid electrolyte LAGP has high lithium ion conductivity (10-4 s / cm) and wide electrochemical window (6V vs Li / Li +), and it is very stable in the air, so it is often used in solid-state lithium air batteries But the tetravalent germanium in LAGP will be reduced to zero or bivalent germanium by lithium In order to protect the solid electrolyte, our group sputtered a layer of nanometer germanium film on the surface of LAGP On the one hand, it inhibited the reduction of tetravalent germanium, on the other hand, it made the electrolyte and lithium contact more closely The solid electrolyte sheet protected by germanium film shows excellent electrochemical performance The solid-state lithium battery assembled by the solid-state electrolyte chip protected by germanium film shows good electrochemical performance The overpotential of the symmetrical battery with germanium film on charge and discharge at the same current is obviously reduced, and it can circulate stably for 200 hours In addition, EIS, SEM, XPS and other means were used to find that the stability of the electrolyte after germanium plating was significantly improved This ingenious method of solid electrolyte protection is helpful to promote the application of solid-state lithium metal batteries Liu Yijie, a 2015 level doctoral student of the school of modern engineering and Applied Sciences, is the first author of the paper, and He Ping and Zhou Haoshen, teachers, are the correspondence authors of the paper This work is supported by national major scientific research projects, National Natural Science Fund, Jiangsu Natural Science Fund and Jiangsu superior discipline Paper link: https://doi.org/10.1002/aenm.201702374 corresponding author: He Ping https://eng.nju.edu.cn/61/bd/c4935a156093/page.htm Zhou Haoshen https://eng.nju.edu.cn/24/41/c5016a140353/page.htm