Functional Polymers for Ionic Thermoelectrics: Multiscale Design Strategies for Ion Dynamics, Mechanics, and Energy Harvesting

Abstract

ABSTRACT The efficient conversion of dissipated heat into useful electrical energy has emerged as a promising approach for sustainable energy technologies. Ionic thermoelectrics (iTEs) are particularly attractive because they generate substantial thermo‐voltages, effectively harvest low‐grade heat, and offer advantages such as cost‐effectiveness, easy scalability, and remarkable performance. Unlike liquid‐state platforms, quasi‐solid‐state iTEs exhibit properties that are critically governed by the polymer matrix and polymer‐ion interactions, which are closely related to the overall device performance. Consequently, the use of functional polymers effectively improves the characteristics and performance of quasi‐solid‐state iTEs. Therefore, this paper highlights the impact of the polymer matrix on performance and mechanical properties in iTEs from molecular‐, micro‐, to macro‐scale engineering. Particular emphasis is placed on clarifying the role of polymers at various scales to provide an in‐depth understanding of performance enhancement. Furthermore, the current challenges and prospective research directions are discussed, offering guidance toward the development of next‐generation iTE‐based energy harvesting platforms.