Related Experiment Video
Updated: Sep 21, 2025
05:33
Solid-state Graft Copolymer Electrolytes for Lithium Battery Applications
Published on: August 12, 2013
21.8K
Understanding the Ionic Conduction in Dielectric Polymers at High Electric Fields Using Molecular Dynamics
Yanhui Huang1, Joakim Jämbeck2, Mikael Unge2
1Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States.
ACS Macro Letters
|June 2, 2022
Summary
Ionic transport in polyethylene exhibits superlinear current increase at high electric fields. Accelerated ions facilitate polymer conformation changes, enhancing mobility beyond 100 MV/m.
Area of Science:
- Materials Science
- Polymer Physics
- Computational Chemistry
Background:
- Understanding ionic transport in polymers is crucial for applications like solid electrolytes.
- Existing theories often fail to fully capture behavior under high electric fields.
Purpose of the Study:
- To investigate ionic transport mechanisms in polyethylene under moderate and high electric fields.
- To compare simulation results with established theories and experimental data.
Main Methods:
- Molecular dynamics simulations were employed to model ion movement.
- Ion mobility was calculated for various species across a range of electric field strengths.
Main Results:
- Ion mobility deviates from the Einstein relation and increases linearly with fields above 100 MV/m.
- A superlinear increase in ionic current was observed at high fields, matching experimental findings.
- Ion mobility enhancement is dependent on ion mass and size.
Conclusions:
- High electric fields accelerate ions, enabling them to induce polymer conformational changes via elastic scattering.
- This process facilitates ion passage and leads to enhanced mobility.
- Ionic transport remains thermally activated but with reduced activation energy due to field-induced energy.
More Related Videos
Related Concept Videos
01:27Electrostatic Boundary Conditions in Dielectrics
1.4K
When an electric field passes from one homogeneous medium to another, crossing the boundary between the two mediums imparts a discontinuity in the electric field. This results in electrostatic boundary conditions that depend on the type of mediums the field propagates through.
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's...
Consider a case where both the mediums across a boundary are two different dielectric materials. Recall that the electric field and electric displacement are proportional and related through the material's...
1.4K
01:31Dielectric Polarization in a Capacitor
5.1K
The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...
5.1K
01:20Electric Field Inside a Conductor
6.4K
When a conductor is placed in an external electric field, the free charges in the conductor redistribute and very quickly reach electrostatic equilibrium. The resulting charge distribution and its electric field have many interesting properties, which can be investigated with the help of Gauss's law.
Suppose a piece of metal is placed near a positive charge. The free electrons in the metal are attracted to the external positive charge and migrate freely toward that region. This region then...
Suppose a piece of metal is placed near a positive charge. The free electrons in the metal are attracted to the external positive charge and migrate freely toward that region. This region then...
6.4K
01:28Induced Electric Dipoles
4.4K
A permanent electric dipole orients itself along an external electric field. This rotation can be quantified by defining the potential energy because the external torque does work in rotating it. Then, the potential energy is minimum at the parallel configuration and maximum at the antiparallel configuration. While the former is a stable equilibrium, the latter is an unstable equilibrium.
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
4.4K
01:26Electric Field at the Surface of a Conductor
4.8K
Consider a conductor in electrostatic equilibrium. The net electric field inside a conductor vanishes, and extra charges on the conductor reside on its outer surface, regardless of where they originate.
In the 19th century, Michael Faraday conducted the famous ice pail experiment to prove that the charges always reside on the surface of a conductor. The experimental set-up consists of a conducting uncharged container mounted on an insulating stand. The outer surface of the container is...
In the 19th century, Michael Faraday conducted the famous ice pail experiment to prove that the charges always reside on the surface of a conductor. The experimental set-up consists of a conducting uncharged container mounted on an insulating stand. The outer surface of the container is...
4.8K
01:17Theory of Metallic Conduction
1.5K
The conduction of free electrons inside a conductor is best described by quantum mechanics. However, a classical model makes predictions close to the results of quantum mechanics. It is called the theory of metallic conduction.
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
In this theory, Newton's second law of motion is used to determine the acceleration of an electron in the presence of an applied electric field. Then, its velocity is expressed via this acceleration.
An electron moves through the crystal, containing positive ions,...
1.5K