Understanding Interfacial-Energy-Driven Dry Powder Mixing for Solvent-Free Additive Manufacturing of Li-Ion Battery Electrodes

Lithium-ion battery electrodes are manufactured using a new additive manufacturing process based on dry powders. By using dry powder-based processing, the solvent and its associated drying processes in conventional battery process can be removed, allowing for large-scale Li-ion battery production to be more economically viable in markets such as automotive energy storage systems. Uniform mixing distribution of the additive materials throughout the active material is the driving factor for manufacturing dry powder-based Li-ion batteries. Therefore, this article focuses on developing a physical model based on interfacial energies to understand the mixing characteristics of the dry mixed particulate materials. The mixing studies show that functional electrodes can be manufactured using dry processing with binder and conductive additive materials as low as 1 wt% due to the uniformly distributed particles. Electrochemical performance of the dry manufactured electrodes with reduced conductive and binder additive is promising as the cells retained 77% capacity after 100 cycles. While not representative of the best possible electrochemical performance of Li-ion batteries, the achieved electrochemical performance of the reduced conductive and binder additive electrodes with LiCoO2 as the active material confirms the well distributed nature of the additive particles throughout the electrode matrix.