Scholarly Work - Chemistry & Biochemistry
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/8714
Browse
2 results
Search Results
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 Bulk Phosphorus-Doped Graphitic Carbon(2018-07) Billeter, Emanuel; McGlamery, Devin; Aebli, Marcel; Piveteau, Laura; Kovalenko, Maksym V.; Stadie, Nicholas P.A direct synthetic route to a tunable range of phosphorus-doped graphitic carbon materials is demonstrated via the reaction of benzene and phosphorus trichloride in a closed reactor at elevated temperatures (800-1050 degrees C). Graphitic materials of continuously variable composition PC,, up to a limit of approximately x = 5 are accessible, where phosphorus is incorporated both substitutionally within the graphite lattice and as stabilized P-4 molecules. Higher temperatures result in a more ordered graphitic lattice, while the maximum phosphorus content is not observed to diminish. Lower temperatures and higher initial phosphorus content in the reaction mixture are shown to correlate with higher structural disorder. Phosphorus incorporation within directly synthesized PC, as both a substitutional dopant and in the form of interstitial, stabilized molecular P-4,d is demonstrated to occur with little oxygen contamination in the bulk (<4 atom %), motivating promising future applications in fuel cells and alkali metal-ion batteries.