Laser Beam Machining of Janus Porous Electrodes for Long‐term Electrophysiological Sensing

Abstract Flexible epidermal electrodes have attracted significant attention for their ability to conform to irregular surfaces, with comfortable and non‐invasive sensing performance. However, challenges remain regarding conformality, breathability, and contact interfacial impedance. This work introduces an ultrathin, trim‐paste, and inexpensive Janus porous electrode by laser beam machining. The micron‐pore‐sized electrodes exhibit exceptional breathability with sweat permeability in less than 1s. In addition, the electrodes exhibit ultrathin profiles, with a thickness of only 23 µm, and an ultralight weight of 0.12 g. Porous electrodes can be trimmed and pasted onto the human skin or objects in a variety of shapes and sizes as required. In particular, the Janus porous kirigami electrodes demonstrate stretchability, with an elongation at break up to 350%. The Janus porous electrodes can be used to detect human electromyography and electrocardiogram signals, showing superior performance compared to commercial gel electrodes, especially in a sweat‐rich environment.