Manufacturing 3-D Lithium-Ion Batteries with Interpenetrating Lattice Electrodes

Author: Zou, Fangyu Nathan

Year: 2023

Degree: Senior thesis (Major)

Advisor: Greer, Julia R.

Committee Member: None, None

Option: Chemical Engineering

DOI: 10.7907/t8n9-wj51

Abstract

3-D lithium-ion batteries have been proven to exhibit a higher energy density while minimizing power loss compared to the standard, layer-by-layer constructed 2-D lithium-ion batteries. This thesis explores the implementation of additive manufacturing in the process of constructing the proposed 3-D battery due to its capability of architecting materials with high accuracy and tunability. A 3-D lithium-ion battery backbone was created using a 2-step process, in which the first step 3-D printed the overall structure as a polymer, and the second step sputtered gold onto the polymer for conductive properties. The 3-D printed battery backbone consisted of two interpenetrating lattices made of post-cured PR48 resin that would serve as the anode and cathode, while the electrolyte would fill the space between the two electrodes. During the sputtering process, the polymer structure was rotated 6 times to guarantee that the sputtering will be conformal throughout the lattice. Electrodeposition was used to generate a LiCoO2 anode and a Li cathode. The electrodeposition of the lithium cobalt oxide cathode onto the lattice structure was proven to be unsuccessful due to the low thermal stability and high reactivity of the 3-D printed polymer when submerged into the electrolyte, consisting of KOH at 260 °C. Results indicate that the uniform electrodeposition of the lithium anode onto the lattice structure was successful using a 1s on, 1s off pulse current for a 60-minute duration. Using a titanium and gold layer proved to increase the uniformity of the coating. However, due to the failure of the lithium cobalt oxide electrodeposition, a different backbone structure may need to be considered. Having two separate structures serving as the anode and cathode (and later combining them into one structure) as opposed to both electrodes being on one structure may be beneficial. This allows for the cathode to be altered without altering both electrodes, allowing more flexibility to coat the structure with lithium cobalt oxide.

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