Antifreezing ionotronic skin based on flexible, transparent, and tunable ionic conductive nanocellulose hydrogels

Ionic hydrogels with excellent flexibility and good conductivity have great potential in diverse electric devices. However, it remains challenging to improve the biocompatibility of ionic hydrogels. Here, natural environment-friendly cellulose nanofiber were prepared without adding any organic active materials. The hydrogel networks free metal ions (Li+/Ca2+/K+) obtained by soaking ion aqueous solution different concentrations order endow tunable conductivity, thus a new kind transparent both sensing performance simple, low-cost harmless process. locked negatively charged nanocellulose network through electrostatic interaction provided adjustable performance. Hydrogels doped 4 mol L?1 lithium exhibited best 4.36 × 10–4 S cm?1, current response value was as high 127%. It worth noting that strain-sensitive calcium generally even at low temperatures (?30 °C). antifreezing improved its service under extreme environment. This has application prospects artificial intelligence products, such human healthy monitoring equipment soft robotics subzero temperature.