Lithium-ion batteries are one of the most widely used batteries due to their high energy density, long cycle life, and low self-discharge. With the rapid development of portable electronics, electrical vehicles, and grid systems, lithium-ion batteries will be more widely employed. However, current slurry based battery electrode manufacturing is costly, preventing wide applications of lithium-ion batteries. The organic solvent typically used in the slurry can be expensive. In addition, a time-consuming and energy-intensive drying procedure has to be employed. The evaporated solvent also needs to be recovered in order to prevent potential environmental pollution. Therefore, it is desirable to have solvent-free battery manufacturing processes. This award supports fundamental research to form the knowledge base for development of solvent-free battery manufacturing processes. Results from this research will enhance the U.S. competence in energy manufacturing industry and benefit the society by providing energy storage solutions.
A major technical challenge in developing solvent-free battery manufacturing processes is to homogeneously disperse battery materials including active materials, conductive additives, and binder materials. This research aims to provide the new knowledge needed to overcome this challenge: (1) interfacial properties of the battery materials, (2) binder distribution characteristics during battery powder mixing, and (3) molten binder wettability and spreading kinetics on other materials during binder melting. The research team will perform multi-scale simulations (molecular dynamics at nanometer scale, finite difference modeling at micrometer scale, and discrete element modeling at micrometer to millimeter scales) to predict interfacial properties, binder spatial distribution after mixing, and molten binder spreading characteristics and surface coverages. Simulation results will be verified by surface energy measurements of dry powders and scanning electron microscopic observations of binder distributions after the powder mixing and binder melting steps respectively.