1. Analysis of Morphological Anisotropy in Rechargeable Batteries
The performance and reliability of porous lithium-ion batteries (LIBs) is dependent on microstructural features, including particle morphology. The power and energy density of a LIB can be tailored for a specific application through engineering of the microstructure. For example, more oblate electrode particles are expected to have a higher reactive surface area – thus improving power density – while sacrificing energy density through increased polarization losses due to the more tortuous structure imposed by the oblate particles. In this context, balancing these competing effects and identifying optimal particle morphologies can be augmented through multiscale simulation.
An extended Newman-type (macrohomogenous) model was developed to allow for the rapid simulation of various electrode particle morphologies. In this project, regimes of high energy density, high power density, and mixed character were identified as a function of particle aspect ratio, along with the underlying mechanisms controlling each regime.
2. Properties of Heterointerfaces in Ionic Solids
Ceramic-Ceramic interfaces, such as those that are found in solid-state batteries or solid oxide fuel cells often possess unique attributes that contribute to properties and charge transfer kinetics that are often detrimental and sometimes favorable for performance. In this project, a multi-phase field theoretical framework is developed to predict the effects of interfacial space charge, composition, and mechanical integrity as a stepping stone to engineer advanced materials and devices for energy applications.
3. Intermetallic Growth in Solder Microbumps
Vertically integrated circuits (3D integrated circuits) require ever-shrinking solder joints to continue the trend of increasing transistor density. As solder joints continue to shrink, the nucleation and growth of intermetallic phases in the joint becomes more prominent as the relative size of the intermetallic region does not shrink with the joint. For this project, a phase field theoretical framework is developed to predict the microstructure evolution of a multicomponent solder joint to identify processing parameters and geometrical features to improve joint integrity and device performance.