In the search of new electrocaloric materials: Fast ion conductors

TL;DR

This study uses molecular dynamics to show that electric fields can significantly lower the superionic transition temperature in CaF2, enabling electrocaloric effects useful for solid-state cooling.

Contribution

It demonstrates how electric fields influence superionic phase transitions in fast ion conductors, revealing potential for electrocaloric cooling applications.

Findings

Electric fields reduce the superionic transition temperature by about 100K.

Large electric fields can deplete ionic conductivity.

Significant electrocaloric effects are observed at the phase transition.

Abstract

We analyse the effects of applying an electric field on the critical temperature, Ts, at which superionicity appears in archetypal fast ion conductor CaF2 by means of molecular dynamics simulations. We find that the onset of superionicity can be reduced by about 100K when relatively small electric fields of ~50KV/cm are employed. Under large enough electric fields, however, ionic conductivity is depleted. The normal to superionic phase transition is characterised by a large increase of entropy, thereby sizeable electrocaloric effects can be realised in fast ion conductors that are promising for solid-state cooling applications.