When two electrolyte-immersed electrodes have different temperatures, a
voltage Δψ can be measured between them. This electrolyte Seebeck
effect is usually explained by cations and anions flowing differently in
thermal gradients. However, our molecular dynamics simulations of aqueous
electrolytes reveal a large temperature-dependent potential drop χ near
blocking electrodes caused by water layering and orientation. The difference in
surface potentials at hot and cold electrodes is more important to the Seebeck
effect than ionic thermodiffusion, Δψ∼χhot−χcold.Comment: Main text: 6 pages with 3 figures. Supplemental material: 5 pages
with 5 figure