The fundamental nature of the ionic thermoelectric ($i$-TE) effect—whether it represents genuine thermoelectricity or merely an analogy—remains unresolved. Existing devices exploit ion migration within the electrolyte but lack interfacial contributions, and no experimental evidence of the Peltier effect in $i$-TE materials has been reported. A central question thus arises: if such a Peltier effect exists, do the Seebeck, Peltier, and Thomson coefficients of $i$-TE systems satisfy the Kelvin relations? Here, we systematically formulate the three thermoelectric effects in the $i$-TE context and provide the experimental observation of an ionic Peltier effect, whose cooling power exceeds that of conventional electrolytes by more than 2 orders of magnitude. Furthermore, we introduce an electromotive-force-based method to determine thermoelectric coefficients without direct heat-flux measurements, thereby enabling experimental verification of the Kelvin relations. These results resolve fundamental questions of the $i$-TE effect and establish its position within thermoelectricity.

Close

PrevNext

View figure in article

• Ionic transport
• Peltier effect
• Thermal convection
• Molecular dynamics