Recently, Professor Yong Zhao’s research group has made new progress in artificial diaphragms to enhance the cycling stability of lithium anodes. The related results are entitled "Inhibiting the shuttle effect using artificial membranes with high lithium-ion content for enhancing the stability of the lithium anode", The full text format is published in Journal of Materials Chemistry A (J. Mater. Chem. A 2020, DOI: 10.1039/c9ta13304f).

The poor cycle stability of the lithium anode is a technical bottleneck for the development of lithium metal batteries. The side reaction between the lithium anode and the functional components of the electrolyte is an important reason for the poor cycle stability of the lithium anode. Existing methods for protecting lithium anodes, such as in-situ solid electrolyte membranes, lithium alloys, and artificial lithium ion conductive membranes, can improve the cycle stability of lithium anodes. However, the above methods are still difficult to meet the long cycle stability of lithium anodes in lithium metal batteries. Requirement, especially when the electrolyte contains different kinds of redox molecules. Therefore, constructing an artificial separator with excellent lithium anode protection effect and high lithium ion conductivity is very important for improving the cycle stability of lithium metal-based batteries.

Schematic diagram of high lithium ion content diaphragm blocking redox molecules from shuttle between positive and negative electrodes

In this work, Yong Zhao’s research group obtained lithium polystyrene sulfonate and lithiated graphene oxide by lithiation treatment of polystyrene sulfonic acid and graphene oxide, and then prepared the above-mentioned materials into composite diaphragms. The electrostatic effect of the lithiated polymer in the separator and the charged groups in the lithiated graphene oxide inhibits the shuttle of redox molecules between the positive and negative electrodes, so as to ensure the excellent lithium ion conductivity of the separator, and realize the long cycling stability of the lithium anode. This research work provides novel ideas and technical means for protecting lithium anodes in lithium metal-based batteries and improving battery cycle stability.

Dong Liang, a master student in the Key Laboratory of Special Functional Materials, is the first author of the paper. This work was strongly supported by the Organization Department of the Central Committee of the Communist Party of China, the National Natural Science Foundation of China, the Henan Provincial Department of Science and Technology, the Henan Provincial Department of Education, and Henan University.

Paper links:

https://pubs.rsc.org/en/content/articlelanding/2020/ta/c9ta13304f#!divAbstract