Design, application, and recycling of zinc alginate/guar gum hydrogel-based fibers

Extreme cold events are quite common, highlighting the urgent need for flexible wearable electronic devices capable of diagnosing human health in low-temperature environments. Using a wet spinning strategy, we successfully developed sodium zinc alginate/guar gum(SZA/GG) hydrogel fibers with excellent environmental resistance, antimicrobial properties, and electrical conductivity. Building on this, we developed a flexible wearable sensing device that operates stably at low temperatures and exhibits a sensitivity of 0.585 within the range of -20 °C to -40 °C, demonstrating excellent response performance. When evaluating the physical state of outdoor athletes, the amplitude and fluctuation range of electrical resistance provide valuable information about the monitored environment and the risk of frostbite for the individual. However, like any device, it eventually reaches its usage limit. To address the issue of recycling hydrogel fiber waste, we propose recycling and carbonizing the discarded devices to use as a biomass carbon source for fabricating button-type supercapacitors. After 10,000 charge-discharge cycles, the capacitance retention rate reached 92.53 %, demonstrating the potential of these supercapacitors and offering a new approach to reducing resource waste.