Synopsis: Plastic Capacitors

Calculations show that combining polymers can improve their dielectic properties and reveal the atomic rearrangements that make this possible.
Synopsis figure
APS/V. Ranjan et al., Phys. Rev. Lett. (2012)

One of the biggest speed bumps hindering widespread adoption of electric vehicles is energy storage: conventional liquid fuels offer a stored energy per unit weight that is hard to beat. The two current approaches to overcoming this limitation are batteries, which use a chemical reaction to generate electricity, or capacitors, which directly store electricity then discharge it when needed. Capacitors take the lead in applications requiring quick delivery of energy. In essence, capacitors are made from two metal surfaces separated by a dielectric; the capacitance can be improved by bringing the surfaces closer together and by using a separator with high dielectric permittivity.

Computer simulations reported in Physical Review Letters by Vivek Ranjan of North Carolina State University, Raleigh, and colleagues predict that mixing a ferroelectric polymer with a pinch of another polymer could yield a sevenfold increase in stored energy compared to the pure dielectric. The calculations offer insights at the molecular level about how this occurs, showing the polymer atoms collectively rearrange from a nonpolar to polar state. Transition paths uncovered by the work have low activation energies and are accessible at technologically reasonable temperatures. The results point the way toward research into creating such optimized polymer dielectrics, which would make capacitive systems roadworthy for powering electric vehicles. – David Voss


Announcements

More Announcements »

Subject Areas

Materials ScienceEnergy Research

Previous Synopsis

Nanophysics

Graphene Nanoribbons Zip Up

Read More »

Next Synopsis

Superconductivity

Universal Pairing Symmetry

Read More »

Related Articles

Synopsis: Starting Fluid for Laser Fusion
Energy Research

Synopsis: Starting Fluid for Laser Fusion

A laser-based fusion experiment demonstrates that liquid fuel capsules could rectify problems encountered with ice-based fuel capsules. Read More »

Focus: Why Some Gels Shrink under Stress
Mechanics

Focus: Why Some Gels Shrink under Stress

The gel material that helps blood clot in a wound has anomalous material properties because of the interaction between the gel's fluid and its microscopic fiber network, according to experiments. Read More »

Synopsis: A New Way to Make Graphene
Graphene

Synopsis: A New Way to Make Graphene

The addition of a rapid-cooling step to the epitaxial growth of graphene on silicon carbide can yield higher-quality graphene sheets. Read More »

More Articles