Publications by authors named "Conor M E Phelan"
Article Synopsis
- Core loss spectroscopies offer detailed insights into redox processes in Li-ion battery cathodes, necessitating precise interpretation of their spectral features, particularly the oxygen K-edge spectra of lithium transition-metal oxides (LiMO).
- Using density-functional theory (DFT), three exchange-correlation functionals were applied to simulate the spectra, with rSCAN showing a better alignment with experimental data compared to PBE and PBE +, especially for energies near the main edge.
- The study demonstrates that DFT can effectively link experimental spectroscopic signatures to theoretical models, revealing the impact of structural distortions, chemical composition, and magnetism on the differentiation of materials with similar structures and magnetic states.
Article Synopsis
- * Research indicates that bulk redox occurs in LiNiO through Ni-O rehybridization without involving trapped molecular oxygen, which is linked to surface degradation.
- * Degradation is characterized by oxygen removal upon discharge and persistent nickel reduction, suggesting the need for effective surface stabilization to improve LiNiO performance.
The cathode-electrolyte interphase (CEI) in Li-ion batteries plays a key role in suppressing undesired side reactions while facilitating Li-ion transport. Ni-rich layered cathode materials offer improved energy densities, but their high interfacial reactivities can negatively impact the cycle life and rate performance. Here we investigate the role of electrolyte salt concentration, specifically LiPF (0.
View Article and Find Full Text PDFThe solid electrolyte interphase (SEI) that forms on Li-ion battery anodes is critical to their long-term performance, however observing SEI formation processes at the buried electrode-electrolyte interface is a significant challenge. Here we show that operando soft X-ray absorption spectroscopy in total electron yield mode can resolve the chemical evolution of the SEI during electrochemical formation in a Li-ion cell, with nm-scale interface sensitivity. O, F, and Si K-edge spectra, acquired as a function of potential, reveal when key reactions occur on high-capacity amorphous Si anodes cycled with and without fluoroethylene carbonate (FEC).
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