Department of Materials Science and NanoEngineering
Rice University, U.S.
Date: July 28, 2021
Time: 1000h ET
Sponsor: Hiden Analytical
During battery (dis)charging, lithium (de)intercalation in electrodes is usually spatially non-uniform across multiple length scales. Such a phenomenon is a major impediment to battery performance and life as it causes energy under-utilization and induces over-(dis)charging, etc. While reaction heterogeneity is often attributed to mass transport limitation, this talk highlights the important roles of thermodynamic factors including elastic energy and phase transformations, the understanding of which is important for the development of mitigation strategies. Through combined modeling and characterization, how stress could destabilize the lithium (de)lithiation front in single crystalline and polycrystalline intercalation compounds is elucidated. Also, a fundamental driving force for dendrite growth on the lithium metal anode during electrodeposition is provided. Stress relief thus offers a promising approach to improving reaction uniformity at the particle level. At the cell level, the reaction distribution that within the porous electrode is strongly influenced by how the electrode’s equilibrium potential varies with the state of charge, is discovered. Two types of prototypical reaction behavior emerge from common electrode materials with significant impact on the thick electrode performance. This finding leads to an efficient analytical model for optimizing battery configurations in place of common battery cell simulations. (more…)