# Gutmann Donor Theory‐Guided Design of Mononuclear Ionic Cluster for Exceptional N‐Type Thermoelectric Ionogel

## TL;DR

This paper introduces a new method for designing high-performance ionic thermoelectric materials using Gutmann donor theory and a three-parameter tuning strategy.

## Contribution

The novel contribution is a systematic design approach for ionic thermopiles based on Gutmann donor theory and structural reconfiguration of ion clusters.

## Key findings

- A negative thermopower of −25.85 mV K−1 and ionic conductivity of 3.21 mS cm−1 were achieved.
- A wearable device prototype with 10 n-type ion thermoelectric capacitors generated 0.774 V at ΔT = 3K.

## Abstract

Quasi‐solid‐state, ionic liquid‐based thermogalvanic gels offer a significant solution for designing ultrasensitive ionic thermopiles due to their exceptional thermopower, superior thermal stability, and high flexibility. Constructing ternary ionogels through ionic doping‐induced ionic aggregates and modulation of ionic transport heat have been proved to be an effective strategy for achieving further enhancement of ionic thermopower. However, the theoretical basis and systematic optimization of ion‐selective doping have not been effectively verified. This study, grounded in the Gutmann donor theory for anion doping, demonstrates four universal configurations of structural reconfiguration in anion/cation clusters within ternary ionogels to progressively enhance anionic transport heat. At 80% relative humidity, this approach achieves a remarkably high negative thermopower of −25.85 mV K−1 and a high ionic conductivity of 3.21 mS cm−1. Furthermore, this work synergistically complements the Gutmann donor anion‐doping strategy by tailoring the structure of the polyacrylate elastomer matrix and the type of cationic dopant. Ultimately, a wearable device prototype integrating 10 n‐type ion thermoelectric capacitors is demonastrated. This device yields a thermally responsive voltage of 0.774 V (ΔT = 3K), demonstrating promise for designing high‐thermopower ionic thermopiles and harvesting low‐grade thermal energy.

Super‐stretchable and self‐healing polyacrylate ternary ionogel elastomers are used for flexible i‐TE devices. Based on Gutmann donor theory of doped anion, the work proposes a three‐parameter tuning strategy of flexible polymer‐doped anion‐synergistic cation to achieve the systematic design of ionic thermoelectric materials.