Scholarly Work - Chemistry & Biochemistry
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/8714
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Item Hydrogen-Type Binding Sites in Carbonaceous Electrodes for Rapid Lithium Insertion(American Chemical Society, 2023-08) McGlamery, Devin; McDaniel, Charles; Xu, Wei; Stadie, Nicholas P.Direct pyrolysis of coronene at 800 °C produces low-surface-area, nanocrystalline graphitic carbon containing a uniquely high content of a class of lithium binding sites referred to herein as “hydrogen-type” sites. Correspondingly, this material exhibits a distinct redox couple under electrochemical lithiation that is characterized as intermediate-strength, capacitive lithium binding, centered at ∼0.5 V vs Li/Li+. Lithiation of hydrogen-type sites is reversible and electrochemically distinct from capacitive lithium adsorption and from intercalation-type binding between graphitic layers. Hydrogen-type site lithiation can be fully retained even up to ultrafast current rates (e.g., 15 A g–1, ∼40 C) where intercalation is severely hampered by ion desolvation kinetics; at the same time, the bulk nature of these sites does not require a large surface area, and only minimal electrolyte decomposition occurs during the first charge/discharge cycle, making coronene-derived carbon an exceptional candidate for high-energy-density battery applications.Item Methodological Studies of the Mechanism of Anion Insertion in Nanometer‐Sized Carbon Micropores(Wiley, 2022-11) Welty, Connor; Taylor, Erin E.; Posey, Sadie; Vailati, Patric; Kravchyk, Kostiantyn V.; Kovalenko, Maksym V.; Stadie, Nicholas P.Dual-ion hybrid capacitors (DIHCs) are a promising class of electrochemical energy storage devices intermediate between batteries and supercapacitors, exhibiting both high energy and power density, and generalizable across wide chemistries beyond lithium. In this study, a model carbon framework material with a periodic structure containing exclusively 1.2 nm width pores, zeolite-templated carbon (ZTC), was investigated as the positive electrode for the storage of a range of anions relevant to DIHC chemistries. Screening experiments were carried out across 21 electrolyte compositions within a common stable potential window of 3.0–4.0 V vs. Li/Li+ to determine trends in capacity as a function of anion and solvent properties. To achieve fast rate capability, a binary solvent balancing a high dielectric constant with a low viscosity and small molecular size was used; optimized full-cells based on LiPF6 in binary electrolyte exhibited 146 Wh kg−1 and >4000 W kg−1 energy and power densities, respectively.