PROGRAM | Mechanical Engineering

By: Soyeon Park Chair: Kelvin Fu

ABSTRACT

Carbon, as a fundamental material class, plays an essential role in various applications due to its exceptional properties and size-related benefits. Additive manufacturing, also known as 3D printing, can be a powerful technique in creating hierarchical 3D carbon architectures with geometric control across different length scales, allowing for integrating mechanical functionalities, such as enhanced stiffness and strength, with additional properties like electrical conductivity. This dissertation seeks to develop universal carbon feedstocks as well as 3D printing/secondary carbonization processes for creating a programmed 3D carbon structure and investigates the potential practical utility and applications of this structure, particularly in advancing lithium-ion batteries.

This study focuses on elucidating the processing-structure-performance relationship in printed 3D carbon structures. It introduces an innovative approach combining Fused Filament Fabrication (FFF) and an optimized post-carbonization process and involves a comprehensive analysis of the processability of feedstocks (i.e., high-loaded carbon composite filaments) from printing to secondary process based on the characterization of their physical and mechanical properties. This manufacturing technique is further explored to create a 3D carbon scaffold with tailored carbon orientation and associated properties required for battery advancement.

With a profound comprehension of the underlying mechanisms, the shear flow inherent in extrusion 3D printing, coupled with secondary carbonization techniques, is utilized to manipulate particle orientation and electrode design across nano to macro scales, resulting in facilitating the production of advanced Lithium-ion batteries with improved Li-ion transport, insertion, and structural stability.

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