A minimal electrostatic theory for the Seebeck coefficient in liquids

TL;DR

This paper introduces a minimal electrostatic model based on solvation entropy to explain the large Seebeck coefficient in liquids, successfully matching experimental magnitudes and identifying key factors influencing the effect.

Contribution

It presents a new electrostatic theory using the extended Born equation to quantitatively explain the Seebeck coefficient in liquids, highlighting the role of dielectric properties and ion characteristics.

Findings

Large valence enhances Seebeck response

Small cationic radius increases Seebeck coefficient

Large temperature derivative of dielectric constant boosts effect

Abstract

The Seebeck coefficient in liquids often reaches the mV/K range, yet its microscopic origin remains unclear due to the complexity of electrolyte systems. Here we propose a minimal electrostatic theory focusing on solvation entropy. Using the extended Born equation with temperature ($T$)-dependent dielectric constant ($\varepsilon$), we quantitatively reproduce the experimentally observed magnitude. The theory clarifies that large valence, small cationic radius, small dielectric constant, and large $\frac{d\varepsilon}{dT}$ are key factors for enhanced liquid Seebeck response.