High-temperature planar heating elements using RuO₂ nanosheets

Planar heating elements employ carbon nanotubes, graphene, and metals. However, the high-temperature (300–500 °C) applications of heating elements based on metallic and organic materials are limited because they oxidize at high temperatures. Oxide materials such as RuO₂ are promising alternatives. The electrical conductivity of heating elements are strongly dependent on the aspect ratios of fillers; thus, RuO₂ nanosheets are suitable fillers for high-temperature planar heating elements because RuO₂ remains stable at high temperatures, and RuO₂ nanosheets have high aspect ratios of over 1000, as the lateral sizes and thicknesses of the RuO₂ nanosheets are 2∼5 μm and 1–3 nm, respectively. Consequently, the electrical conductivity of planar heating elements using RuO₂ nanosheets as fillers is 940 times higher than that of heating elements using conventional granular RuO₂ nanoparticles. Therefore, the RuO₂ nanosheet-based heating elements will be suitable in various applications requiring high temperatures and high uniformity.