Advanced Mycelium Skins for Sustainable Electronics

Abstract Developing sustainable substrates for electronics is key to reduce the global reliance on fossil‐based synthetic polymers. Mycelium‐based materials are emerging as promising alternatives as they up‐cycle agricultural wastes and offer biodegradability. However, their often inhomogeneous growth and relatively rough surface limit their applicability, especially for thin‐film electronics. Here, post‐growth treatments such as deacetylation of chitin that modify the structure and composition of the mycelium and improve its mechanical and electrical characteristics are introduced. The resulting mycelium foil demonstrates extended durability, reduced electrical conductivity, and a reduced surface roughness R rms of 2.7 ± 0.7 µm while maintaining its thermal stability and biodegradability. Metallic thin films deposited onto these foils exhibit conductivities as high as 18.08 ± 2.38 × 10 4 Scm −1 and withstand more than 10000 bending repetitions. Coating the mycelium foil with biodegradable shellac further smoothens its surface and provides moisture resistance. In addition, it serves as an adhesive for the lamination of copper (Cu) layers which, structured by laser ablation, enable flexible electronic devices such as a Near‐Field‐Communication‐Tag. The recovery of non‐biodegradable components is moreover enabled through triggered dissolution in ethanol. These developments in mycelium‐based electronics offer viable solutions to promote eco‐friendly manufacturing processes and ultimately reduce electronic waste.