An ultrahigh stretchable wearable self-powered hydrogel sensor driven by body heat

Abstract

Flexible wearable hydrogel sensing devices have attracted significant attention in recent years. However, the integration of high stretchability, body heat-driven self-powering capabilities, and effective strain sensing performance into a single hydrogel poses a significant challenge. In this study, a polyacrylamide (PAM)–laponite XLG (clay)–LiCl hydrogel (PCLH) was fabricated by a simple one-pot synthesis technique at room temperature. The hydrogen bonds formed between PAM and clay, combined with the incorporation of LiCl, facilitate clay dispersion and enhance the stretchability of the hydrogel. Furthermore, the migration of Li+ and Cl− driven by temperature gradients allows the hydrogel to exhibit remarkable thermoelectric properties. The PCLH demonstrates ultrahigh stretchability, with an elongation at break of 6610%, and possesses thermoelectric characteristics, featuring a Seebeck coefficient of 15.32 mV K−1. Based on the excellent stretchability and thermoelectric performance of PCLH, we developed a self-powered wearable sensor that harvests electricity from the temperature difference between the human body and the ambient environment. This device, which is driven by body heat, operates in two distinct working modes—resistive and voltage—making it a promising solution for human motion sensing applications.