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 heatto-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 H 2 O/ 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.
The emergence of portable health monitors and wearable versatile sensors brings a promising approach for real‐time physiological surveillance. However, the complicated wiring connections and unsustainable power supplies have largely hindered their combination. Herein, a human body‐based electrode‐free triboelectric nanogenerator (TENG) is demonstrated, which can not only effectively harvest biomechanical energy from human walking and running, but can also serve as a self‐powered versatile inartificial physiological monitor. Most importantly, no electrode material is required in the TENG. In virtue of triboelectrification between the sole and the floor, electricity is produced during human motions with the desirable open‐circuit voltage of more than 150 V under casual walking. The performance of the TENG is investigated under variable environmental conditions and different configurations to evaluate its adaptability. By extracting inartificial electric signals from any part of the human body, information of the footwork, lameness, body weight, and jumping height can be actively transmitted out without using any external power sources. This work provides a new self‐powered route of health surveillance and disease diagnosis.
MoS
2
nanochains were successfully prepared via facile
electrospinning and a hydrothermal process. The morphology of MoS
2
nanochains was evaluated by field emission scanning electron
microscopy and high-resolution transmission electron microscopy. A
slurry composed of the MoS
2
nanochains was coated on a
silver electrode to detect ammonia. The detection range of ammonia
was between 25 and 500 ppm. MoS
2
nanochains offered outstanding
sensing response, repeatable reproducibility, and excellent selectivity
with a detection limit of 720 ppb. The responsiveness of MoS
2
nanochains to ammonia remained unchanged for 1 week.
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