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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Metal–Ligand Redox Cooperativity in Cerium Amine-/Amido-Phenolate-Type Complexes
Not provided.
The H•/H– Redox Couple and Absolute Hydration Energy of H–
A supermolecule-continuum approach with water clusters up to n = 16 H2O molecules has been used to predict the absolute hydration free energies at 298 K ($\Delta$G hyd ) of both hydrogen (H•) and hydride (H - ) to be 4.6 and -78 ± 2 kcal/mol, respectively. These values are combined with a high accuracy prediction of the gas phase electron affinity ($\Delta$G gas,298K = -16.9 kcal/mol) to determine the aqueous electron affinity of H• of 99.5 ± 2 kcal/mol, which yields a reduction potential for H• vs SHE of -0.03 ± 0.15 V. This value is in agreement within 0.2 V with most estimates obtained using a wide variety of approaches. The results of this study can be used to improve the absolute hydricity scale in water which provides additional insights into how a putative hydride interacts with solvent, but do not change the ability to predict the relative reactivity of two species using relative hydricity scales.
Charge and Solvent Effects on the Redox Behavior of Vanadyl Salen–Crown Complexes
Not provided.
Comparative Study of Organic Radical Cation Stability and Coulombic Efficiency for Nonaqueous Redox Flow Battery Applications
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Predicting Anion Redox in Secondary Battery Cathode Materials with a Data-Driven Model
Not provided.
Electrolyte Vapor Induced Passivation and Transition Metal Redox on Electrode Active Materials
The gaseous environment that battery electrodes are exposed to is critical to their electrochemical performance, and yet, the impact of vapor-phase components in the glovebox is relatively unexplored. In this study, we examine how the surface of Li 4 Ti 5 O 12 and LiFePO 4 composite electrodes evolve upon exposure to 1 M LiPF 6 in ethylene carbonate:dimethyl carbonate electrolyte vapors in an argon-filled glovebox. Spatially resolved X-ray photoemission electron microscopy and X-ray photoelectron spectroscopy reveal that even brief (15 minutes) contact with electrolyte vapor initiates the formation of a LiF film and changes the oxidation state of transition metals at the particle surface. Notably, these modifications occur selectively on active material particles and not on binder or conductive carbon, underscoring the specificity of vapor-induced reactions. Prolonged exposure to electrolyte vapor over the course of 1 week yields thicker, more chemically complex interphases containing both LiF and lithium oxyfluorophosphate species (Li x PO y F z ). Subsequent electrochemical testing shows that vapor-induced passivation layers influence first cycle capacities, lithium (de)insertion overpotentials, and charge-transfer resistance values. In conclusion, these results indicate that vapor–electrode interactions may be a source of variability in electrochemical behavior over time and suggest that other, more reactive electrode materials may also be susceptible to interactions with electrolyte vapor.
Synthesis and Characterization of Dense Carbon Films as Model Surfaces to Estimate Electron Transfer Kinetics on Redox Flow Battery Electrodes
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