Self-Powered Respiratory Monitoring Strategy Based on Adaptive Dual-Network Thermogalvanic Hydrogels

As a low-grade sustainable heat source, the breath waste heat exhaled by human bodies is always ignored, although producing a greater temperature than ambient. Converting this heat into electric energy for use as power sources or detecting signals is extremely important in cutting-edge wearable medicine. This heat to-electricity conversion is possible with thermogalvanic hydrogels. However, challenges remain in their antifreezing and antidrying properties, significantly restricting the durability of thermogalvanic gels in practical applications. Herein, a dual-network poly(vinyl alcohol)/gelatin (PVA/GEL) gel thermogalvanic device with Fe(CN)63-/4- as a redox pair is developed, with an outstanding low-temperature durability and antidrying capacity. These features result from the use of a binary H2O/ GL (glycerin) solvent to limit hydrogen bonding between water molecules. The prepared thermogalvanic gel patch is capable of easily converting physiological data into understandable electrical impulses using the temperature difference between the ambient environment and the heat produced by human breathing, realizing a simple self-powered respiratory monitoring strategy for the first time. Even below zero temperature, the gel patch-based mask can operate normally, implying it fits into low-temperature environments. This study sheds fresh light on the development of active wearable medical electronics that are powered by demic low-level heat.

Automated summary

The waste heat exhaled by human bodies, which is often ignored, can be converted into electric energy for use in wearable medical devices. A dual-network poly(vinyl alcohol)/gelatin gel thermogalvanic device with outstanding low-temperature durability and antidrying capacity has been developed. By limiting hydrogen bonding between water molecules using a special solvent, physiological data can be converted into electrical impulses for respiratory monitoring.