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Department of Chemistry

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Browsing Department of Chemistry by Subject "3D batteries"

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    Extending the life of electrochemically deposited anodes in 3D sodium ion batteries with cPAN
    (Colorado State University. Libraries, 2025) Medina, Dylan, author; Prieto, Amy, advisor; Rappe, Anthony, committee member; Nazemi, Reza, committee member
    Humanity constantly seeks to improve the simplicity of their lives, and as such develops technologies to assist with this endeavor. Almost all of these technologies rely on electricity. From large stationary objects to the small mobile devices we see everywhere, they must be charged. For some this means operation almost exclusively on a battery, for others they rely on constant power from the power grid, and most use a rechargeable battery charged from the power grid as a blend. But even power stations have limits for how much they can generate at a time and need to rely on power generated during low demand times to supplement higher demands, and such the power grid also relies on batteries. Chapter I discusses the basis of why energy storage is so important, the history of the modern lithium-ion battery, and where storage technology is heading to improve supplemental battery types. The basics of why sodium ion batteries are attractive as a supplement to lithium-ion batters is outlined. Finally, the geometries of 3D batteries are described, and a key feature leading to uneven distribution of material on 3D electrodes is highlighted. Chapter II focuses on developing a procedure to cyclize polyacrylonitrile (PAN) to act as a binder to keep material in electrical contact to the anode current collector after it fractures and separates. Simple equipment such as a dip coater and a tube furnace are used to evenly coat the substrate with the precursor, which is then annealed to form cPAN. Verification of the cyclization of PAN to form cPAN is done via Fourier Transform Infrared (FTIR) analysis, and sample thickness is measured using scanning electron microscopy (SEM). Once the procedure for the fabrication steps is verified, the actual anodes must be made. In chapter III, cyclic voltammetry is used to get the correct parameters for sample electrodeposition and the anodes are made. After samples were annealed with a layer of cPAN, SEM and energy-dispersive X-ray spectroscopy (EDS) are used to characterize the samples. There is a detailed discussion for the fabrication of a pouch half-cell, and some trends observed when they are evaluated as an electrode using battery cycler. Chapter IV attempts to get a realistic application by placing cPAN coated anodes in a full cell and placing them on a battery cycler. Every step along the way was characterized by measuring the internal resistance, which is noted as an indicator of how or why the cells may be acting abnormally. In conclusion, the overlap of each section is summarized and discussed. The hypothesis for why the cells do not cycle effectively is that the polymer is too thick. Future work will focus on repeating the coating of cPAN onto antimony anodes but with better control over thickness. Refinements to the process such as a thinner polymer layer, calendaring, and a better contact and compression system could provide insight and useful results in the future.