Thermodynamic Design Strategy for Ionic Thermoelectric Polymer Complexes with Giant Thermopower and Power Density

Abstract

Ionic thermoelectric (TE) materials offer great promise for self-powered wearable electronics due to their ability to convert low-grade heat into electricity with ultrahigh thermovoltages. However, their performance remains limited by an incomplete understanding of the thermodynamic factors governing ionic TE efficiency. Here, a thermodynamically guided design strategy is reported for high-performance p- and n-type ionic TE polymer complexes. By tailoring the interplay between ions and polymer matrices through controlled synthetic approaches, record-high ionic figures of merit (ZT i) of 49.5 and 32.2 are achieved, and outstanding normalized power densities of 46.7 and 79.0 mW<middle dot>m-2<middle dot>K-2. A flexible p/n-type ionic TE module delivers a remarkable voltage output of 1.03 V<middle dot>K-1 and a normalized power density of 981 mW<middle dot>m-2<middle dot>K-2. This module powers a commercial LED under a temperature gradient of just 1.5 K, without external amplification. These results offer a practical and scalable path toward wearable energy harvesting systems based on ionic TEs.