Dual-modal hydrogels with synergistically enhanced mechanical-thermoelectric performance for intelligent wearable sensing and automotive temperature feedback systems

The advancement of flexible quasi-solid-state thermoelectric cells (TECs) presents new possibilities for wearable electronics. However, challenges such as mechanical strength, temperature sensitivity, and limited power output hinder broader applications. This study proposes a dual strategy to enhance both mechanical properties and thermoelectrochemical performance of TECs using [Fe(CN)₆]^3–/4–. By leveraging the Hofmeister effect and non-covalent interactions, the mechanical strength of NIPAM hydrogel electrolytes was increased from 4.86 kPa to 38.9 kPa through the addition of [2-(methacryloxy)ethyl]dimethyl-(3-sulfonatopropyl)ammonium hydroxide (MEMSA) and polar solvent DMF, achieving an extensibility of nearly 2500 %. Additionally, modifications with MEMSA hydroxide and guanidine hydrochloride improved the solvation structure of [Fe(CN)₆]^3–, resulting in an enhanced Seebeck coefficient from 0.72 to 5.632 mV K^–1. The developed quasi-solid-state TECs demonstrated a power density of 0.624 mW m^-²·K^-², showing marked performance improvements. The material's properties, based on NIPAM and MEMSA, also support a wide operating temperature range. Furthermore, an intelligent remote-controlled car was designed featuring a temperature feedback system powered by deep learning algorithms, allowing for real-time monitoring and control, thus showcasing significant potential for future wearable electronic applications.