Effects of Coherency Strain in Phase Separating Li-ion Battery Materials
Martin Bazant (MIT), Daniel Cogswell (Samsung SAIT America), Todd Ferguson ()
Lithium ion batteries: When Chemistry meets Mechanics
Tue 2:40 - 4:00
Salomon 003
Elastic coherency strain plays a critical role in the electrochemical behavior of Li-ion batteries, especially for intercalation hosts such as iron phosphate and graphite, which phase separate into multiple metastable states with different lattice constants. A general theory of charge-transfer kinetics, transport and phase separation is developed based on nonequilibrium thermodynamics. The theory is applied to lithium iron phosphate cathodes and graphite anodes for Li-ion batteries. It is shown that coherency strain is a key to achieving quantitative accuracy in predicting single-particle phase morphologies, reaction kinetics, nucleation barriers, and the intercalation dynamics of porous electrodes.