Atomistic insights into Li-ion diffusion in amorphous silicon

Yan, Xiang-Ping; Gouissem, Afif; Sharma, Pradeep

doi:10.1016/j.mechmat.2015.04.001

Cited by 29 publications

(21 citation statements)

References 32 publications

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“…We note that the MAMD method follows the conventional MD procedures and cannot account for processes whose transition times exceed microseconds. Recently, a collection of algorithms including the potential energy surface sampling method has been successfully employed to assess the mechanical behavior of a nanopillar under strain rate from 1 to 10 8 s −1 (Fan et al, 2013;Yan et al, 2015;Yan and Sharma, 2016). This algorithm can be adopted by the MAMD method, which is under future investigation.…”

Section: Basic Assumptionsmentioning

confidence: 99%

Atomistic simulation for deforming complex alloys with application toward TWIP steel and associated physical insights

Wang

Liu

et al. 2017

Journal of the Mechanics and Physics of Solids

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A B S T R A C TThe interest in promoting deformation twinning for plasticity is mounting for advanced materials. In contrast to disordered grain boundaries, highly organized twin boundaries are beneficial to promoting strength-ductility combination. Twinning deformation typically involves the kinetics of stacking faults, its interplay with dislocations, as well as the interactions between dislocations and twin boundaries. While the latter has been intensively studied, the dynamics of stacking faults has been rarely touched upon. In this work, we report new physical insights on the stacking fault dynamics in twin induced plasticity (TWIP) steels. The atomistic simulation is made possible by a newly introduced approach: meta-atom molecular dynamics simulation. The simulation suggests that the stacking fault interactions are dominated by dislocation reactions that take place spontaneously, different from the existing mechanisms. Whether to generate a single stacking fault, or a twinning partial and a trailing partial dislocation, depends upon a unique parameter, namely the stacking fault energy. The latter in turn determines the deformation twinning characteristics. The complex twin-slip and twin-dislocation interactions demonstrate the dual role of deformation twins as both the dislocation barrier and dislocation storage. This duality contributes to the high strength and high ductility of TWIP steels.

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Section: Basic Assumptionsmentioning

confidence: 99%

Atomistic simulation for deforming complex alloys with application toward TWIP steel and associated physical insights

Wang

Liu

et al. 2017

Journal of the Mechanics and Physics of Solids

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“…The first approach can be used to study atomistic systems without loading or with constant stress [43,44]:…”

Section: Methods 1: No Mechanical Loading or Constant Stress Loadingmentioning

confidence: 99%

Section: Rate Constantsmentioning

confidence: 99%

Atomistic modeling at experimental strain rates and timescales

Yan

Cao

Wen

et al. 2016

J. Phys. D: Appl. Phys.

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In 1934, G I Taylor made what is now a historical speculation: that atomistic defects called 'dislocations' are responsible for the ductile 'plastic' deformation of metals [1]. Were the scientists of that time to have had recourse to molecular dynamics (MD) algorithms and modern computers, this would not have been mere speculation, and direct evidence of dislocation-mediated plasticity would be at hand. This arguably artificial scenario underscores the power of conventional MD simulations to provide microscopic insights into material behavior that sometimes may not be easily discernible experimentally 4. Indeed, conventional MD, which simply consists

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“…There are however some notable exceptions, Mendez et al [22] recently used the so-called diffusive molecular dynamics to examine the process of lithiation in silicon nanopillars. Two of the co-authors of the present work, previously, have used a timescaling approach based on the potential energy sampling method to understand both Li-ion diffusion and the unit plastic event in fully lithiated silicon nanostructues identifying the rotation of the shear transformation zones as the main dissipation mechanism [23,24].…”

Section: Introductionmentioning

confidence: 99%

An Atomistic Perspective on the Effect of Strain Rate and Lithium Fraction on the Mechanical Behavior of Silicon Electrodes

Darbaniyan

Yan

Sharma

2019

Journal of Applied Mechanics

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The process of charging and discharging of lithium-ion batteries results in the periodic intercalation and ejection of lithium ions in the anode material. High-capacity anode materials that are of significant interest for next-generation batteries, such as silicon, undergo large deformation during this process. The ensuing electro-chemo-mechanical stresses and accompanying microstructural changes lead to a complex state of inelastic deformation and damage in the silicon electrode that causes a significant capacity loss within just a few cycles. In this study, we attempt to understand, from an atomistic viewpoint, the mechanisms underlying the plasticity behavior of Si-anode as a function of lithiation. Conventional molecular dynamics simulations are of limited use since they are restricted to loading rates in the order of 108 s−1. Practical charging-discharging rates are several orders of magnitude slower, thus precluding a realistic atomistic assessment of the highly rate-dependent mechanical behavior of lithiated silicon anodes via conventional molecular dynamics. In this work, we use a time-scaling approach that is predicated on the combination of a potential energy surface sampling method, minimum energy pathway, kinetic Monte Carlo, and transition state theory, to achieve applied strain rates as low as 1 s−1. We assess and compare the atomistic mechanisms of plastic deformation in three different lithium concentration structures: LiSi2, LiSi, and Li15Si4 for various strain-rates. We find that the strain rate plays a significant role in the alteration of the deformation and damage mechanisms including the evolution of the plastic deformation, nucleation of shear transformation zone, and void nucleation. Somewhat anomalously, LiSi appears to demonstrate (comparatively) the least strain rate sensitivity.

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Atomistic insights into Li-ion diffusion in amorphous silicon

Cited by 29 publications

References 32 publications

Atomistic simulation for deforming complex alloys with application toward TWIP steel and associated physical insights

Atomistic simulation for deforming complex alloys with application toward TWIP steel and associated physical insights

Atomistic modeling at experimental strain rates and timescales

An Atomistic Perspective on the Effect of Strain Rate and Lithium Fraction on the Mechanical Behavior of Silicon Electrodes

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