Collaborative Research: Battery Electrode Fabrication through Innovative Powder based Additive Manufacturing

锂离子电池具有能量密度高、循环寿命长、自放电小等优点，是目前应用最广泛的电池之一。随着便携式电子产品、电动汽车和电网系统的快速发展，锂离子电池将得到更广泛的应用。然而，目前基于浆料的电池电极制造成本很高，阻碍了锂离子电池的广泛应用。通常在浆料中使用的有机溶剂可能很昂贵。此外，一个耗时和能源密集的干燥过程必须采用。蒸发的溶剂也需要回收，以防止潜在的环境污染。因此，希望有无溶剂电池制造工艺。该奖项支持基础研究，以形成无溶剂电池制造工艺开发的知识库。该研究成果将提高美国能源制造业的竞争力，并通过提供储能解决方案造福社会。开发无溶剂电池制造工艺的主要技术挑战是均匀分散电池材料，包括活性材料、导电添加剂和粘合剂材料。本研究旨在提供克服以下挑战所需的新知识：(1)电池材料的界面特性；(2)电池粉末混合过程中的粘结剂分布特性；(3)粘结剂熔化过程中熔融的粘结剂润湿性和在其他材料上的扩散动力学。研究团队将进行多尺度模拟（纳米尺度的分子动力学，微米尺度的有限差分建模，微米到毫米尺度的离散元建模）来预测界面性质，混合后粘合剂的空间分布，以及熔融粘合剂的扩散特征和表面覆盖率。模拟结果将分别通过干粉的表面能测量和粉末混合和粘结剂熔化步骤后粘结剂分布的扫描电镜观察来验证。

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.