Trehalose-enhanced ionic conductive hydrogels with extreme stretchability, self-adhesive and anti-freezing abilities for both flexible strain sensor and all-solid-state supercapacitor

Flexible strain sensors and flexible supercapacitors have generated a lot of interest because of their great potential to be used in flexible electronic equipment. Ionic hydrogels are ideal for the preparation of strain sensors and supercapacitor electrolytes, so the design of a multifunctional ionic conductive hydrogel is the key to obtain both high-performance strain sensors and flexible all-solid-state supercapacitors. During our work, trehalose and LiCl were added concurrently to the P(AM-co-AA) polymer network to prepare a multifunctional ionic conductive hydrogel combining ultra stretchability (elongation at break up to 4529%), high ionic conductivity, self-adhesive and freeze-resistant moisturizing properties. The ionic conductive hydrogel was encapsulated into a strain sensor, which has excellent sensing performance, achieving a great detection range (0–4200%) and high sensitivity (GF = 3.59 in the strain range of 2200–4200%). The strain sensor was applied to human motion detection, demonstrating precise detection behavior for joint flexion and muscle movement. The ionic conductive hydrogel was assembled with flexible fabric electrodes loaded with carbon nanotubes (CNTs) and MXene to form a sandwich-type supercapacitor. The supercapacitor exhibited high areal capacitance (148.2 mF/cm2), excellent cycling performance, outstanding stability and good low temperature resistance.