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、自放电低等优点，是目前应用最广泛的电池之一。随着便携式电子、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较高，阻碍了锂离子电池的广泛应用。浆料中通常使用的有机溶剂可能很昂贵。此外，还必须采用耗时和耗能的干燥程序。蒸发的溶剂也需要回收，以防止潜在的环境污染。因此，希望有无溶剂的电池制造工艺。该奖项支持基础研究，以形成开发无溶剂电池制造工艺的知识库。这项研究的结果将提高美国在能源制造行业的竞争力，并通过提供能源储存解决方案造福社会。开发无溶剂电池制造工艺的一个主要技术挑战是均匀分散电池材料，包括活性材料、导电添加剂和粘结剂材料。这项研究旨在提供克服这一挑战所需的新知识：(1)电池材料的界面性质，(2)电池粉末混合过程中粘结剂的分布特征，以及(3)粘结剂熔化过程中熔融粘结剂在其他材料上的润湿性和扩散动力学。研究小组将进行多尺度模拟(纳米尺度的分子动力学、微米尺度的有限差分模拟和微米至毫米尺度的离散元素模拟)，以预测界面性质、混合后粘结剂的空间分布以及熔体粘结剂的扩散特性和表面覆盖率。模拟结果将分别通过干粉表面能测量和粘结剂混合后粘结剂分布的扫描电子显微镜观察来验证。

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.