Anion Defect Chemistry for Advanced Battery Materials

• Applicant: Professor Dr. Jürgen Janek
• Subject Area: Solid State and Surface Chemistry, Material Synthesis ; Synthesis and Properties of Functional Materials
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 514846489

Advanced lithium-ion batteries (LIBs) are one of the most promising and realistic candidates for large-scale energy storage from renewable energies. For a large-scale use of LIBs, the low specific capacity and short lifetime of the cathode active material (CAM) need to be improved. Therefore, developing high-energy-density and robust CAMs is vitally important. Cation modification is a widely accepted strategy to improve battery performance, yet this conventional strategy is approaching its limitation. For the progress of battery materials utilizing anion functionality, establishing fundamental understanding of anion defect engineering is of key importance. Therefore, the goal of this project is establishing anion defect chemistry for battery CAMs and provide guidelines for the development of mixed-anion CAMs. To achieve this goal, the joint team will work on two research topics through this project:1) Revealing the oxygen defect formation mechanism and their impact on battery performance.2) Introduction of hetero-anion defects and the investigation of anion defect functionality.Clearly, lack of fundamental knowledge on anion defect species in battery CAMs impedes the progress of advanced battery materials based on anion mixing strategy. The significance of this work is establishing the fundamental science of anion defect chemistry, for anion defect engineering of battery materials which will result in rational guidelines for high-energy-density and robust battery materials. Although this is a very challenging topic, the complementary joint approach can pave the way to this goal by combining our unique methodologies; the Japanese team will evaluate and control anion defect species in battery CAMs, and the German team will evaluate anion/cation diffusion kinetics and reveal the impact of anion defects on electrochemical charge/discharge reactions. Both teams have excellent track records in their respective fields. For the establishment of anion defect chemistry for CAMs, we will tackle two problems in this project: One is to establish oxygen defect chemistry, and the other is the understanding of the functionality of hetero-anion defects in battery CAMs.

• DFG Programme: Research Grants
• International Connection: Japan
• Cooperation Partners: Professor Dr. Koji Amezawa; Professor Dr. Takashi Nakamura