On the thermopower of ionic conductor and ionic capacitors

TL;DR

This paper provides a theoretical analysis of the thermoelectric response in ionic conductors, revealing that their thermopower behavior differs fundamentally from electronic conductors and depends on system charge exchange conditions.

Contribution

It introduces a theoretical framework showing how charge exchange conditions affect thermopower in ionic conductors, highlighting differences from electronic materials.

Findings

Thermopower expressions differ for open and closed systems.

In zero-current steady state, thermopower is independent of mobilities.

Ionic conductors' behavior is rooted in distinct conservation laws.

Abstract

We theoretically study the thermoelectric response of ionic conductors to an applied temperaturegradient. As a main result we find that open and closed systems with respect to charge exchange,result in different expressions for the thermopower which may even take opposite signs. For theexperimentally most relevant zero-current steady state, we show that the thermopower of ionic conductorsdoes not depend on the mobilities, contrary to what is known for metals and semiconductors.The different behavior of ionic and electronic conductors is traced back to the unlike conservationlaws for ionic carriers and electron-hole pairs.