| 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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Carrasco, Javier
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (5/5 displayed)
- 2021Towards tuning the modality of hierarchical macro-nanoporous metals by controlling the dealloying kinetics of close-to-eutectic alloyscitations
- 2019Fluorine‐Free Noble Salt Anion for High‐Performance All‐Solid‐State Lithium–Sulfur Batteriescitations
- 2016Variation in surface energy and reduction drive of a metal oxide lithium-ion anode with stoichiometrycitations
- 2016Unveiling the electrochemical mechanisms of the Li 2 Fe(SO 4 ) 2 polymorphs by neutron diffraction and density functional theory calculationscitations
- 2016Variation in surface energy and reduction drive of a metal oxide lithium-ion anode with stoichiometry:a DFT study of lithium titanate spinel surfacescitations
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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.