Battery performance and its fade are determined by various aspects such as the transport of ions and electrons through heterogeneous internal structures; kinetic reactions at the interfaces; and the corresponding interplay between mechanical, chemical, and thermal responses. The fundamental factor determining this complex multiscale and multiphysical nature of a battery is the geometry of active materials. In this work, we systematically consider the tradeoffs among a selection of limiting geometries of media designed to store ions or other species via a diffusion process. Specifically, we begin the investigation by considering diffusion in spheres, rods, and plates at the particle level, in order to assess the effects of geometry, diffusivity, and rate on capacity. Then, the study is extended to considering of the volume fraction and particle network, as well as kinetics at the interface with electrolyte. Our study suggests that, in terms of overall bulk level material performance, thin film batteries may generate the highest energy density with high power capability when they are implemented at nanoscales or with highly diffusion materials.
Available at: http://works.bepress.com/jonghyun-park/10/