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A review on modeling of electro-chemo-mechanics in lithium-ion batteries
2019/01/09
New Publication in “Journal of Power Sources”
Investigations on the fast capacity loss of Lithium-ion batteries (LIBs) have highlighted a rich field of mechanical phenomena occurring during charging/discharging cycles, to name only a few, large deformations coupled with nonlinear elasticity, plastification, fracture, anisotropy, structural instability, and phase separation phenomena. …
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Phase‐Field Study of Electromechanical Coupling in Lead‐Free Relaxor/Ferroelectric‐Layered Composites
2018/12/28
New Publication in “Advanced Electronic Materials”
Here, we direct investigate different coupling effect by introducing soft and charge interphase layers in the serial‐type layer composite model. A new relaxor phase‐field model is first developed to reproduce this phase transition and parameterized by fitting the measured hysteresis loops. …
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Rapid-Heating-Triggered in Situ Solid-State Transformation of Amorphous TiO2 Nanotubes into Well-Defined Anatase Nanocrystals
2018/12/14
New Publication in “Crystal Growth & Design”
Fabrication of nanocrystals from their disordered solid-state precursors represents a new synthetic strategy. Herein, we report a rapid-heating-triggered in situ solid-state crystal growth method capable of transforming amorphous TiO2 nanotubes into anatase nanocrystals with well-defined facets and uniform sizes within a minute. …
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Impact of interface structure on magnetic exchange coupling in MnBi/FexCo1−x bilayers
2018/11/29
New Publication in “Physical Review B”
Magnetic exchange coupling behavior was investigated in MnBi/FeCo bilayer system at the hard/soft magnetic interface. We performed a combined study of cross-sectional high resolution transmission electron microscopy (HR-TEM), DFT calculations, and micromagnetic simulations to elucidate effect of interface structure on exchange coupling. …
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An extended grain boundary barrier height model including the impact of internal electric field
2018/11/21
New Publication in “AIP Advance”
An extended phenomenological model is proposed to rationalize the potential barriers of the varistor like boundaries of piezoelectric semiconductors. This model takes self-consistently into account the inverse piezoelectric effect of the internal electric field associated with the barrier height at grain boundaries. …
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Coupled phase field simulations of ferroelectric and ferromagnetic layers in multiferroic heterostructures
2018/10/30
New Publication in “Archive of Applied Mechanics”
A state-of-the-art approach is used for the ferroelectric layer. The material behavior of the ferromagnetic layer is described by a continuum formulation from the literature, which is discretized using a newly proposed approach for the consistent interpolation of the magnetization vector. …
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Correlation between mechanical strength of amorphous TiO2 nanotubes and their solid state crystallization pathways
2018/10/26
New Publication in “Chemistry Select”
Developing TiO2 crystals with specific morphologies and nanostructured architectures is highly desirable in energy storage, conversion and catalysis applications. Herein, we report a close correlation between mechanical strength of the TiO2 precursors and their different crystallization pathways. …
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Enabling nanoscale flexoelectricity at extreme temperature by tuning cation diffusion
2018/10/25
New Publication in “Nature Communications”
Any dielectric material under a strain gradient presents flexoelectricity. Here, we synthesized 0.75 sodium bismuth titanate −0.25 strontium titanate (NBT-25ST) core–shell nanoparticles and observed domain-like nanoregions (DLNRs) up to an extreme temperature of 800 °C. …
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The influence of anisotropic surface stresses and bulk stresses on defect thermodynamics in LiCoO2 nanoparticles
2018/07/28
New Publication in “Acta Materialia”
The focus of this study is the distribution of surface-induced bulk stresses in a LiCoO2 nanoparticle and their impact on the migration of Li-vacancies. At these length scales, surface effects gain an appreciable impact not only on the electrochemical and mechanical behavior of the electrode material, but also on defect thermodynamics. …
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Tailoring the electrocaloric effect by internal bias fields and field protocols
2018/07/16
New Publication in “Physical Review Applied”
In this work we study the impact of internal bias fields on the electrocaloric effect (ECE), utilizing an analytical model and ab-initio-based molecular dynamics simulations. We reveal the complex dependency of the ECE on field protocol and relative strength of internal and external fields. …