| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Morgan, Benjamin
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (6/6 displayed)
- 2022Transition metal migration and O2 formation underpin voltage hysteresis in oxygen-redox disordered rocksalt cathodescitations
- 2021Understanding Fast-Ion Conduction in Solid Electrolytescitations
- 2019Impact of Anion Vacancies on the Local and Electronic Structures of Iron-Based Oxyfluoride Electrodescitations
- 2019Impact of non-parabolic electronic band structure on the optical and transport properties of photovoltaic materialscitations
- 2016The stability of the M2 phase of vanadium dioxide induced by coherent epitaxial straincitations
- 2016Variation in surface energy and reduction drive of a metal oxide lithium-ion anode with stoichiometrycitations
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article
Variation in surface energy and reduction drive of a metal oxide lithium-ion anode with stoichiometry
Abstract
Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> is a “zero-strain” lithium-ion anode material that shows excellent stability over repeated lithium insertion–extraction cycles. Although lithium (de)intercalation in the bulk material has been well characterised, our understanding of surface atomic- scale–structure and the relationship with electrochemical behaviour is incomplete. To address this, we have modelled the Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> (111) , Li<sub>7</sub>Ti<sub>5</sub>O<sub>12</sub> (111) and α-Li<sub>2</sub>TiO<sub>3</sub> (100), (110), and (111) α-Li<sub>2</sub>TiO<sub>3</sub> surfaces using Hubbard-corrected density- functional theory (GGA+<i>U</i>), screening more than 600 stoichiometric Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> and Li<sub>7</sub>Ti<sub>5</sub>O<sub>12</sub> (111) surfaces. For Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> and Li<sub>7</sub>Ti<sub>5</sub>O<sub>12</sub> we find Li-terminated surfaces are more stable than mixed Li/Ti-terminated surfaces, which typically reconstruct. For α-Li2TiO3, the (100) surface energy is significantly lower than for the (110) and (111) surfaces, and is competitive with the pristine Li<sub>7</sub>Ti<sub>5</sub>O<sub>12</sub> (111) surface. Using these stoichiometric surfaces as reference, we also model variation in Li surface coverage as a function of lithium chemical potential. For Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub>, the stoichiometric surface is most stable across the full chemical potential range of thermodymamic stability, whereas for Li<sub>7</sub>Ti<sub>5</sub>O<sub>12</sub>, Li deficient surfaces are stablised at low Li chemical potentials. The highest occupied electronic state for Li<sub>7</sub>Ti<sub>5</sub>O<sub>12</sub> (111) is 2.56 eV below the vacuum energy. This is 0.3 eV smaller than the work function for metallic lithium, indicating an extreme thermodynamic drive for reduction. In contrast, the highest occupied state for the α-Li<sub>2</sub>TiO<sub>3</sub> (100) surface is 4.71 eV below the vacuum level, indicating a substantially lower reduction drive. This result demonstrates how stoichiometry can strongly affect the thermodynamic drive for reduction at metal-oxide–electrode surfaces. In this context, we conclude by discussing the design of highly-reducible metal-oxide electrode coatings, with the potential for controlled solid-electrolyte–interphase formation via equilibrium chemistry, by electrode wetting in the absence of any applied bias.