Sweat could power wearables

A new power generator concept could let people charge fitness trackers and smartwatches with their own perspiration ( Device 2024, DOI: 10.1016/j.device.2024.100356 ). The flexible generator, which could be embedded in a wristband or headband, harnesses energy from evaporating sweat and produces electricity. The device is a type of hydroelectric nanogenerator (HENG). "Its working mechanism is pretty fascinating," says Jingliang Li , a chemical engineer at Deakin University. HENGs have porous substrates loaded with functional materials that absorb water and split it into positive and negative ions, which line up along the substrate's channels. As some water evaporates, capillary force drives more water past the charged channel walls, generating an electric current. Researchers have made similar generators before using carbon particles or nanotubes, but the output power has been low because the particles clump together. Li, Azadeh Nilghaz , and colleagues used MXenes, which are 2D layered transition- metal carbides