High-thermopower ionic thermoelectric hydrogel with gradient immobilization of anions by polypyrrole

초록

Ionic thermoelectric (i-TE) materials, which convert heat into electricity via the Soret effect, have attracted considerable interest due to their high thermopower and excellent flexibility. Restricting the thermal diffusion of either cations or anions has been demonstrated as an effective strategy to enhance thermoelectric performance; however, existing studies remain largely limited to systems with uniform concentration distributions. In this work, we develop a P-type thermoelectric hydrogel, denoted as PVA/PPy/GF@5.00%SDBS, which achieves a giant Seebeck coefficient of 21.5 mV & sdot;K- 1, representing 2.5-fold and 7-fold enhancements over uniformly immobilized and pristine systems, respectively. This exceptional performance is enabled by a gradient immobilization strategy that restricts anion diffusion while simultaneously increasing the Eastman entropy associated with cation transport. Collectively, these findings elucidate the role of ion immobilization in modulating the Soret effect and establish a new paradigm for controlling ion migration in i-TE systems.

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