Rational tuning and thermodynamic characterization of Lithium silicides and lithium iron phosphate as electrode materials for lithium ion batteries - Calorimetric, kinetic and theoretical investigations of the relations between reactivity, morphology and size effects

• Applicants: Professor Dr. Jens Kortus; Professor Dr. Florian Mertens
• Subject Area: Thermodynamics and Kinetics as well as Properties of Phases and Microstructure of Materials ; Synthesis and Properties of Functional Materials
• Term: from 2010 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 180078959

The project is an integrated approach to provide fundamental materials property data for two of the most promising electrode materials (i.e. LixSi - anöde, LiFePO4 - cathode) that are the base for many recent developments and investigations in lithium ion battery research and to utilise it in theoretical studies to quantitatively model and understand the processes that determine the morphology and morphologic changes induced by the battery Operation. Special focus in these investigations, experimentally äs well äs theoretically, will be on nano-structured modifications of the base materials. The methods applied encompass the experimental determination of thermodynamic data of the various phases of the Li-Si and the Li-Fe-P-O2 phase diagrams by different calorimetric methods, the determination of kinetic data by time resolved calorimetric (heat flux) measurements, and the morphological characterisation. These activities are met by theoretical investigations of the various phases by OFT and linear-response techniques, the Identification of new phases by evolutionary algorithms, the Provision of diffusion data by molecular dynamics calculations, and the analysis of spatially spreading phase transitions and their influence on morphology by phase-field simulations. Part of the theoretical contribution will be the development of adjusted models and the implementation in current Software.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1473: Materials with New Design for Improved Lithium Ion Batteries - WeNDeLIB
• Participating Persons: Privatdozent Dr. Michael Fleck; Dr. Regina Hüttl; Dr. Jürgen Seidel