Understanding Non-Uniformities in 3D Lithium-Ion Battery Electrode Architectures

Abstract

Conventional Lithium-ion intercalation batteries that are composed of planar cathode, separator, and anode layers have an intrinsic trade-off between energy density and power density. While thick electrodes allow for more active material loading and higher energy densities, thick electrodes lengthen ion transport pathways and limit power performance. Conversely, thin electrodes have fast ion transport at the cost of reduced material loading which leads to lower energy densities. Three-dimensional (3D) batteries can potentially mitigate this power and energy trade-off through electrode architecture. Unlike planar electrodes, 3D batteries have unique and integrated electrode architectures that can modify ion transport pathways in three-dimensions on a micron to millimeter scale. These architectures may be locally imbalanced in material loading, leading to nonuniform current density and local depletion of the electrode or electrolyte material. These nonuniformities can terminate a discharge or charge cycle prematurely. Although many 3D battery architectures have been proposed to date, few comparative modeling studies have been conducted for these architectures to understand their relative performance gains.In this presentation, we will investigate the impact of 3D electrode architecture on current density uniformity and material lithiation at different discharge rates in several 3D batteries. Our batteries are simulated using the software CAEBAT: AMPERES 1 , which provides a 3D electrochemical model on the continuum level using volume-averaging techniques. 3D batteries with different parameterizations and geometries of interdigitated anode and cathode electrodes are studied. In addition, the effects of current collector placement, material loading, and electrode feature shapes are also presented.1. Allu, S., Kalnaus, S., Simunovic, S., Nanda, J., Turner, J. A., and Pannala, S., J. Power Sources, 325, 42 (2016)