Additive Manufacturing of Structured Electrodes for Lithium-Ion Batteries

Demand for increased performance, lower cost, and lower environmental impact, there is a growing interest in electrode structural design and shape fabrication. There is an opportunity to improve lithium-ion battery performance, sustainability, and safety by scaling up and integrating structured electrode manufacturing processes. Current battery electrode manufacturing, which includes slurry coating and drying, to produce electrode films is energy and time-intensive, contains significant quantities of environmentally toxic solvents, and lacks processability controlling electrode thickness and geometric complexity. Advanced manufacturing processes have been developed to produce thick-structured electrodes with improved performance and safety characteristics. For example, mechanical tools, such as lasers and punchers, have been used to create through-thickness holes, and electromagnetic fields and conductive templates also have been applied to lower tortuosity for improved structural alignment. Both energy density and power can be significantly increased but with limited success, and these manufacturing processes require additional systems, which are quite challenging to scale beyond lab research. Additive manufacturing, also known as 3D printing, is a trend to produce battery electrodes with complex physical structures and compositions to simultaneously achieve high-energy and high-power electrodes at a low cost. However, existing 3D printing strategies have fabricated electrodes using ink-based slurries that lack the ability to form complex geometries or narrow-range UV-curable resins that lack ion and electric transport capabilities.<br/>To overcome materials and manufacturing limitations, we developed a dry electrode processing route, Structured Electrode Additive Manufacturing (SEAM), to rapidly and efficiently fabricate out-of-plane aligned thick electrodes with low tortuosity and mechanically robustness. This additive manufacturing can manipulate the structure of anisotropic nanomaterials across nano to macro scales and create free-standing complex 3D geometries with minimal volume changes, high thermo-mechanical stability. In addition, dry electrode formation allows to simplify electrode manufacturing steps and significantly reduce production energy intensity without using any solvents or the drying process. SEAM can manipulate multiscale structural details by orienting the anisotropic geometrical features of active materials (e.g., graphite flakes) along with their longitudinal directions at high-pressure induced shear flow and deposition. The printed graphite thick electrodes have an out-of-plane alignment structure, which facilitates lithium-ion transport and battery electrode insertion, leading to high-energy and high-power batteries.