(Invited) Enabling Rechargeable Conversion Cathodes By Modeling the Coupling between Structure, Electrochemistry, and Mechanics

While traditionally used as a primary battery chemistry, there is current interest in using FeS2 as a high-energy density cathode material for specialized rechargeable battery applications. However, the combination of intercalation and conversion processes, large volume change upon reaction, and the formation of polysulfides complicate its cycling behavior and therefore wider adoption. We present computational models at both the mesoscale (particle-resolved) and macroscale (homogenized) that look at the coupled interplay between mechanical stress and strain and electrochemistry to determine the performance and degradation of FeS2 electrodes. These models are used to explore the role of particle size polydispersity and additively manufactured 3D-structured electrode designs (e.g. pillars) to appropriately balance mechanics, transport, and kinetic limitations and optimize electrode performance. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.