(258c) Utilization of MEMS Techniques to Deterministically Engineer High Power Li-Ion Battery Electrodes

Rechargeable, or secondary batteries, are required to power almost all of today's increasingly complex technology. Thus, new systems must be created to match the size and power needs of these devices. In most current commercial batteries, high charge and discharge rates lead to increased kinetic resistances and reduced capacity retention. Increasing electrode size and active material mass can increase energy storage but reduces power density. In order to optimize both energy storage and power performance, the battery electrodes must be designed to minimize the kinetic resistances of both electron and ion transport within the system while maintaining the infrastructure to hold a large amount of active material. Additionally, it is necessary for these electrodes to be deterministically engineered in order to have potential for high volume manufacturing. In this study, micromachining and electroplating techniques are utilized to design a fabrication process that deterministically engineers electrodes and achieves the goal of both high power and high energy density performance. The fabrication process maximizes the surface area of the electrodes, while the multilayer approach enables the manufacture to be repeatable and scalable, up to volumes on the order of a cm³. The power performance of the electrodes is characterized through galvanostatic charge and discharge and analysis of the effect of C rate on capacity retention and cyclability.