Stretchable Triboelectric Self‐Powered Sweat Sensor Fabricated from Self‐Healing Nanocellulose Hydrogels

Abstract Though visualizing perspiration constituents is crucial for physiological evaluation, inadequate material healing and unreliable power supply methods restrict its applications. Herein, a fully flexible self‐powered sweat sensor is fabricated from a cellulose‐based conductive hydrogel to address these issues. The hydrogel electrode is composed of a cellulose nanocomposite polymerized in situ with polyaniline and cross‐linked with polyvinyl alcohol/borax. The cellulose nanocomposites furnish the sweat sensor with tensile and electrical self‐healing efficiencies exceeding 95% within 10 s, a stretchability of 1530%, and conductivity of 0.6 S m −1 . The sweat sensor quantitatively analyzes Na + , K + , and Ca 2+ contents in perspiration, to sensitivities of 0.039, 0.082, and 0.069 mmol –1 , respectively, in real time via triboelectric effect and wirelessly transmits the results to a user interface. This fabricated sweat sensor with high flexibility, stability, and analytical sensitivity and selectivity provides new opportunities for self‐powered health monitoring.