Examining the Impact of Different copper Foil Configurations on the Efficiency of Lithium Titanate Oxide Anode in Lithium-ion Batteries

  • Abdellah Assam

Student thesis: Master's Thesis

Abstract

In the current landscape of lithium-ion batteries (LIBs), most commercial electrodes are coated on standard copper foil without surface roughness or any surface treatment. However, a rougher surface can provide more contact area with the electrode material, potentially enhancing electrical conductivity and improving adhesion. This can result in better performance and longer lifespan, allowing for more charging and discharging cycles without losing contact with the current collector. Additionally, surface treatments with materials that have superior electrical conductivity could further enhance cell performance.
This research investigates the impact of advanced electrode component on lithium-ion battery (LIB) performance, focusing specifically on the application of (LTO) active material to various copper foils with distinct structures and modifications.
The primary goal is to assess how different foils influence the performance of LIBs with LTO-coated electrodes and to determine the optimal coating thickness to increase the areal loading capacity while maintaining cell performance.
The foils used in this research are as follows: a standard copper foil produced using the knife roll process, featuring an almost flat surface and a thickness of 15 µm; a galvanically modified copper foil with a thickness of 15 µm; an Argalin-modified copper foil with a thickness of 12 µm and an inorganic chromoxide protection layer of 2-5 nanometers; a Superdip-modified copper foil with a thickness of 12 µm and an organic tetrazole-derivative protection layer; and a thick copper foil with a thickness of 30 µm and a roughness of 1-5 µm, without a protection layer. The same thick copper foil was treated with sulfuric acid to reduce the oxidation layer and tested accordingly.
The research involves a series of comprehensive analyses, including viscosity tests to evaluate the rheological properties of the LTO slurry, essential for the coating process, and SEM to examine the coating's surface morphology and uniformity. Adhesion and cohesion tests were conducted to assess the mechanical integrity of the LTO-electrode layers on the copper foils, while electrochemical tests, including charging and discharging cycles at different C-rates, measure key battery performance metrics such as capacity, efficiency, and stability.
Findings reveal that while most anode types maintain robust adhesion, those coated on argalin modified copper foils exhibit significant adhesion failures, leading to reduced electrical conductivity and overall performance degradation. Cells with standard copper foil anodes of 100 μm and those on galvanically modified copper foils at thicknesses of 100 and 200 μm consistently outperform other modifications, particularly highlighting the negative impact of oxidation layers on copper foil over time.
The results highlight the importance of selecting appropriate copper foil modifications and optimizing coating thickness and material composition to enhance the structural integrity and electrochemical efficiency of battery anodes. These insights guide the design of more reliable and efficient LIBs and provide directions for future research. The findings aim to achieve better cell performance and higher areal loading capacities while maintaining cell integrity.
Date of AwardSept 2024
Original languageEnglish
SupervisorChristina Toigo (Supervisor)

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