| 1. |
- Källquist, Ida, et al.
(författare)
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Potentials in Li-Ion Batteries Probed by Operando Ambient Pressure Photoelectron Spectroscopy
- 2022
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 14:5, s. 6465-6475
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Tidskriftsartikel (refereegranskat)abstract
- The important electrochemical processes in a battery happen at the solid/liquid interfaces. Operando ambient pressure photoelectron spectroscopy (APPES) is one tool to study these processes with chemical specificity. However, accessing this crucial interface and identifying the interface signal are not trivial. Therefore, we present a measurement setup, together with a suggested model, exemplifying how APPES can be used to probe potential differences over the electrode/electrolyte interface, even without direct access to the interface. Both the change in electron electrochemical potential over the solid/liquid interface, and the change in Li chemical potential of the working electrode (WE) surface at Li-ion equilibrium can be probed. Using a Li4Ti5O12 composite as a WE, our results show that the shifts in kinetic energy of the electrolyte measured by APPES can be correlated to the electrochemical reactions occurring at the WE/electrolyte interface. Different shifts in kinetic energy are seen depending on if a phase transition reaction occurs or if a single phase is lithiated. The developed methodology can be used to evaluate charge transfer over the WE/electrolyte interface as well as the lithiation/delithiation mechanism of the WE.
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| 2. |
- Shi, Hao, et al.
(författare)
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Corrosion behavior of Al-containing MAX-phase coatings exposed to oxygen containing molten Pb at 600 degrees C
- 2022
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Ingår i: Corrosion Science. - : Elsevier. - 0010-938X .- 1879-0496. ; 201
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Tidskriftsartikel (refereegranskat)abstract
- Four types of MAX-phase coating samples (Cr2AlC, V2AlC, Ti2AlC, and Ti3AlC2), synthesized via physical vapor deposition and post-annealing of elemental multilayer films, have been investigated toward their potential corrosion protection in 10(-6) wt% oxygen-containing molten Pb for 3200 h at 600 degrees C. Three MAX-phase coatings (Cr2AlC, Ti2AlC, and Ti3AlC2) are corrosion resistant against the molten Pb, via formation of a protective oxide layer. Specifically, various oxide scales formed on each sample: an Al2O3 scale, containing a low amount of Cr2O3 was formed in case of the Cr2AlC coating; a mixed Al2O3 and TiO2 oxide scale was observed for both Ti2AlC and Ti3AlC2 coatings. A more complex mixed oxide layer consisting of VO2, V4O7, and Pb-3(VO4)(2) phases is formed on the V2AlC coating, while the MAX-phase coating was almost entirely consumed. According to their corrosion performance against oxygen containing molten Pb, the order of corrosion resistance is: Cr2AlC > Ti2AlC > Ti3AlC2 > V2AlC.
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