Silver-nickel core-shell nanostructure on cellulose fibers as biodegradable wearable paper heater

In this study, the traditional Korean Hanji or Han-paper, comprising cellulose fibers obtained from mulberry bark, was coated with silver nanowires (AgNWs) via supersonic spraying; this was followed by electroplating with nickel to produce a silver-nickel (AgNW-Ni) core-shell nanostructure, thereby protecting the nanostructures of the AgNWs from thermal breakdown. The Hanji cellulose fibers coated with the core-shell AgNW-Ni were used as a paper heater. The nickel electroplating time was increased to thicken the nickel shell enwrapping the AgNWs. The electrical properties of the Hanji heater were investigated to identify the optimal AgNW-Ni core-shell nanostructure. The surface temperature of the AgNW-Ni Hanji heater reached 125 degrees C at 7 V without thermal breakup of the AgNWs with long-term stability. Under excessive electroplating, the entire Hanji substrate was covered with nickel. In this scenario, a nickel layer was formed over the Hanji, which substantially reduced the electrical resistivity of the layer. This metal-metal core-shell nanostructure can be attached to any type of substrate, including rigid alumina, polyethylene terephthalate, and bulk plastic; this makes the method versatile and widely applicable. Stringent bending radius and cyclic tests confirmed the mechanical durability and thermal stability of the silver-nickel core-shell Hanji heater.

Automated summary

In this study, traditional Korean Hanji paper was coated with silver nanowires (AgNWs) via supersonic spraying and followed by electroplating with nickel to create a silver-nickel (AgNW-Ni) core-shell nanostructure for thermal protection. The AgNW-Ni Hanji paper heater showed stable long-term performance at a surface temperature of 125°C under 7V. The metal-metal core-shell nanostructure could be applied to various substrates and demonstrated mechanical durability and thermal stability.