The overall objectives of the proposed research were to acquire fundamental knowledge related to new battery manufacturing processes. Specifically, the project aimed to conduct fundamental research to provide essential knowledge for the development of a room temperature manufacturing process capable of creating 3D structures, overcoming the limitations of conventional electrodes. The new process facilitated multiscale-controlled manufacturing of 3D porous metal oxide parts without thermal damage, including control over microstructure features and macroscale geometry. The primary outcomes of the project are outlined as follows: In the initial study (published in Advanced Energy Materials), a novel approach for thickening electrodes, known as µ-casting, was introduced. This method enabled the creation of ultrathick electrodes, addressing the trade-off between specific capacity and areal/volumetric capacity. The µ-casting process, based on a patterned blade, allowed for the facile fabrication of 3D electrode structures, demonstrating improvements in battery energy/power performance. The study delved into the properties of µ-casted ultrathick electrodes, showcasing enhanced energy density, cell stability, and high-performance characteristics, including high-mass loading, higher specific capacity, and areal capacity after cycles.

Subsequently, a hyper-thick electrode exceeding 700 µm was achieved through a μ-EF process, wherein electric field processing was incorporated into the μ-casting process. The μ-EF electrodes proved to be a breakthrough in battery technology, demonstrating high capacity, superior diffusivity, and reduced stress generation. The micro-macro architecture facilitated enhanced charge transfer, resulting in an exceptional cycle life with stable capacity. This approach achieved an exceptional areal capacity of ~8 mAh/cm2 by arranging active material particles in a regular pattern, promoting better ion movement and enabling a short diffusion path. The study marks a new era in battery technology, offering insights into ionic diffusion characteristics, particle-level synchronization of active materials, remarkable capacity, and impressive mechanical properties, particularly in hyper-thick electrodes. The work has the potential to revolutionize electric vehicle battery technology, providing a practical demonstration of theoretical hypotheses through comprehensive experimental analysis.

Regarding education, three PhD students and two undergraduate students participated in the project, gaining exposure to cutting-edge battery manufacturing and characterization. Training in fabrication, assembly of lithium-ion battery coin cells, battery testing, and characterization has equipped them with skills and critical thinking for their future careers. One PhD student has already graduated, and two more students are expected to graduate in 2024 and 2026, respectively. For the dissemination of research outcomes, two journal papers based on this project have been published, with three manuscripts pending. The PIs or their PhD students have presented their findings in 10 presentations.

Furthermore, the project emphasizes the interplay between constituent particles and their assembled network in many engineering devices. The strategic arrangement of materials has the potential to produce properties and advantages that outperform those resulting from random distribution. However, the practical application of this concept faces challenges due to a limited understanding of the intricate relationships among geometry, particle networks, particle mobility, engineering processes, and device performance. This lack of comprehension impedes manufacturing control, particularly when dealing with solutions containing high solids loading. The project's objective is to bridge these knowledge gaps by investigating how fabrication parameters govern structures and examining the impact of these structures on system responses. The findings are widely applicable across various disciplines, providing valuable insights into manufacturing control for devices characterized by organized material distributions.

Last Modified: 12/19/2023
Modified by: Jonghyun Park