(Invited) Layered Electrodes for Lithium-Ion Batteries

Abstract

Development of lithium-ion batteries has dramatically boosted market adoption of electric vehicles. However, extending driving range is still necessary to further widespread adoption of lithium-ion batteries in electric vehicles, which relies on increased energy density. Increasing electrode areal loading is one effective approach to boost energy density as it reduces the weight fraction of current collectors and the volume fraction of separators, which do not contribute to battery capacity [1]. However, increased energy density in thick electrodes is usually achieved at the expense of power density mainly due to transport limitation of lithium ions through the porous electrodes. This results in electrolyte depletion and lower utilization of the electrodes [2].To tackle the sluggish mass transport rates, novel electrode architectures are required. There have been various methods for creating unique electrode architectures to reduce electrode tortuosity and facilitate lithium ion diffusion, including laser ablation, co-extrusion, advanced slot-die coating, and freeze tape casting [3-5]. In this presentation, we will discuss design of layered electrodes for superior energy and power performance. Results from both experiment and simulation are included where effect of particle size of active materials, thickness ratio between layers and electrode porosity in each electrode layer were explored. It is demonstrated that the appropriate layered structure can more than double the power density compared to a traditional one. Acknowledgment This research at Oak Ridge National Laboratory (ORNL), managed by UT Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725, was sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Advanced Manufacturing Office (AMO).