New progress in research and development of new solid-state lithium metal organic batteries

Due to its good safety and high theoretical capacity, the research and development of solid-state lithium metal batteries with solid-state electrolytes instead of liquid electrolytes has attracted much attention, so the development of solid-state electrolytes is also particularly important. The reporter learned from the College of Materials and Energy of Yunnan University on the 17th that the team of Professor Guo Hong of the College has recently made the latest progress in the research and development of new solid-state lithium metal organic batteries, and the international journal "Carbon Energy" has published relevant research results.

Previous research and production mainly focused on inorganic electrolytes such as sulfides, halides, and oxides. However, these solid electrolytes have shortcomings such as rigidity and air sensitivity, which affect the interfacial stability and cycle and rate performance of batteries.

In recent years, organic polymer electrolytes have gradually attracted attention due to their advantages such as flexibility and being easy to form films. Covalent organic framework materials are a kind of carrier for promising single-ion solid electrolyte, but researchers need to study the number of active sites in depth, and the effect of skeleton structure on lithium ion conductivity, migration number and battery performance.

Based on the current research status and problems, and combined with the previous research foundation, Professor Guo Hong's team designed and prepared three kinds of covalent organic frame single lithium ion conductor material regulated by lithium carboxylate. From the effects of different framework structures and the number of active sites on the conductivity and migration number of lithium ions, combined with theoretical calculations, they deeply studied the electrostatic potential distribution of the three materials, and used density functional theory calculations to analyze the migration path of lithium ions and energy barrier difference.

Subsequently, the research team assembled a quasi-solid-state battery with lithium metal as the negative electrode, organic small molecule cyclohexanone as the positive electrode, and the constructed single-ion conductor as the solid-state electrolyte.

The results of performance tests and theoretical calculations show that single-ion conductors can effectively inhibit the growth of lithium crystals, and quasi-solid-state batteries can solve the dissolution of organic small-molecule cathode materials in electrolytes. This strategy provides important theoretical basis and technical support for high-efficiency quasi-solid-state lithium metal organic batteries.

Source: Science and Technology Daily