ORCID Profile
0000-0001-7966-750X
Current Organisation
University of Oxford
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Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 05-2013
Publisher: American Chemical Society (ACS)
Date: 25-08-2014
DOI: 10.1021/NN503564R
Abstract: Surface passivation of silicon anodes is an appealing design strategy for the development of reliable, high-capacity lithium-ion batteries. However, the structural stability of the coating layer and its influence on the lithiation process remain largely unclear. Herein, we show that surface coating mediates the swelling dynamics and the fracture pattern during initial lithiation of crystalline silicon nanopillars. We choose conformally nickel coated silicon architectures as a model system. Experimental findings are interpreted based on a chemomechanical model. Markedly different swelling and fracture regimes have been identified, depending on the coating thickness and silicon nanopillar diameter. Nanopillars with relatively thin coating display anisotropic swelling similar to pristine nanopillars, but with different preferred fracture sites. As the coating thickness increases, the mechanisms become isotropic, with one randomly oriented longitudinal crack that unzips the core-shell structure. The morphology of cracked pillars resembles that of a thin-film electrode on a substrate, which is more amenable to cyclic lithiation without fracture. The knowledge provided here helps clarify the cycling results of coated nanosilicon electrodes and further suggests design rules for better performance electrodes through proper control of the lithiation and fracture.
Publisher: Wiley
Date: 03-2012
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9SM00796B
Abstract: Discrete networks simulations are conducted to decorrelate the effects of density and topology on the elasticity of near-ideal random networks.
Publisher: Springer Science and Business Media LLC
Date: 06-2013
Publisher: Elsevier BV
Date: 06-2015
Publisher: Elsevier BV
Date: 11-2016
Publisher: Elsevier BV
Date: 03-2010
Publisher: Elsevier BV
Date: 12-2018
Publisher: AIP
Date: 2011
DOI: 10.1063/1.3589642
Publisher: Elsevier BV
Date: 12-2011
Publisher: Wiley
Date: 30-01-2018
Publisher: Elsevier BV
Date: 04-2020
Publisher: Elsevier BV
Date: 04-2015
Publisher: Elsevier BV
Date: 07-2019
Publisher: Elsevier BV
Date: 10-2020
Publisher: World Scientific Pub Co Pte Lt
Date: 09-2012
DOI: 10.1142/S1758825112500238
Abstract: An electrode in a lithium-ion battery may undergo inelastic processes of two types: flow and reaction. Flow changes the shape of the electrode, preserves its composition and volume, and is driven by the deviatoric stress — a process similar to the plastic flow of a metal. By contrast, reaction changes the composition and volume of the electrode, and is driven by a combination of the mean stress and the chemical potential of lithium in the environment. Both flow and reaction are mediated by breaking and forming atomic bonds. Here we formulate a continuum theory of large-deformation electrodes by placing flow and reaction on the same footing. We treat flow and reaction as concurrent nonequilibrium processes, formulate a thermodynamic inequality and a rheological model, and couple the two processes through a chemomechanical flow rule. Within this theory, the driving force for reaction — the mean stress and the chemical potential — can stimulate flow in an electrode too brittle to flow under a mechanical load alone. For an electrode under vanishingly small stress and current, cyclic lithiation and delithiation can cause hysteresis in the voltage-concentration curve. For a thin-film electrode bonded on a substrate, cyclic lithiation and delithiation can cause hysteresis in both the voltage-concentration curve and the stress–concentration curve.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 07-05-2021
Abstract: Materials that can cycle between states are of interest for actuators, soft robotics, or recoverable membranes for separations. Chang et al. show that a collection of graphene oxide fibers can fuse into a single stronger fiber upon immersion in a solvent, extraction, and drying under tension (see the Perspective by Cruz-Silva and Elías). The geometrical deformation of the fibers during drying and swelling plays an important role in the reversible cycles, with a large volume change between the dried and swelled fibers. Moreover, fibers made from polymers, glass, metal, or silk can be given these abilities when coated with a micron-sized layer of graphene oxide. Science , this issue p. 614 see also p. 573
Publisher: Elsevier BV
Date: 12-2023
Publisher: Elsevier BV
Date: 2013
Publisher: Elsevier BV
Date: 02-2022
Publisher: Elsevier BV
Date: 10-2022
Publisher: Elsevier BV
Date: 03-2019
Publisher: ASME International
Date: 24-09-2014
DOI: 10.1115/1.4028587
Abstract: Pure substances can often be cooled below their melting points and still remain in the liquid state. For some supercooled liquids, a further cooling slows down viscous flow greatly, but does not slow down self-diffusion as much. We formulate a continuum theory that regards viscous flow and self-diffusion as concurrent, but distinct, processes. We generalize Newton's law of viscosity to relate stress, rate of deformation, and chemical potential. The self-diffusion flux is taken to be proportional to the gradient of chemical potential. The relative rate of viscous flow and self-diffusion defines a length, which, for some supercooled liquids, is much larger than the molecular dimension. A thermodynamic consideration leads to boundary conditions for a surface of liquid under the influence of applied traction and surface energy. We apply the theory to a cavity in a supercooled liquid and identify a transition. A large cavity shrinks by viscous flow, and a small cavity shrinks by self-diffusion.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 03-2011
Publisher: The Royal Society
Date: 09-2018
Abstract: An original procedure is developed for simulating pore surface evolution during sintering at high strain rate while distinguishing two types of diffusion fluxes: transient surface fluxes governed by short-range curvature gradients and coupled fluxes at surface and grain boundary governed by strain rate. The latter fluxes become dominant asymptotically, i.e. after d ing-out of transient fluxes. The procedure aims at allowing the prediction of the strain rate dependence of macroscopic viscosity, a concept which is meaningful only during the asymptotic stage. The problem is addressed in two-dimension. It is shown that the asymptotic solution of the general partial differential equation of the problem can be obtained as the solution of an ordinary differential equation, of which the resolution lends itself to a semi-analytical procedure. An estimate is also proposed for the rate of convergence of the general solution towards the asymptotic solution. The accuracy of the mathematical procedure is validated by a comparison of the evolution of asymptotic profiles and exact profiles calculated fully numerically during densification or expansion of the system. A method is proposed for mapping the conditions of existence of an asymptotic stage. The method can account for the dependence of average grain coordination on relative density.
Publisher: Elsevier BV
Date: 05-2018
Publisher: Elsevier BV
Date: 03-2018
Publisher: Elsevier BV
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 08-2009
Publisher: Elsevier BV
Date: 04-2013
Publisher: Elsevier BV
Date: 12-2016
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 10-2019
Publisher: Elsevier BV
Date: 07-1970
Publisher: Wiley
Date: 21-09-2018
DOI: 10.1111/JACE.16058
Publisher: Elsevier BV
Date: 05-2016
Publisher: Elsevier BV
Date: 10-2015
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
Location: No location found
No related grants have been discovered for Laurence Brassart.