Abstract: Electronic companies must continuously innovate to meet the growing demand for safety, reliability, environmental sustainability, and cost-effective designs. Recently, there has been increasing interest from researchers, industry, and government in developing eco-friendly electronic materials that dissolve completely after use, leaving behind harmless byproducts. This work presents an example of an energy storage device based on completely biodegradable and low-cost materials, created by assembling bio-based polymers with carbonaceous fillers. Polymeric materials derived from renewable resources, such as proteins, starch, and cellulose, were processed into plastic-like products with desirable structural and functional properties. Their hydrophilic nature, rapid degradation, and chemical complexity allow these materials to serve multiple functions, from structural support to barrier protection. Notably, the ability of biopolymers to bind low-molecular-weight species (e.g., water and glycerol) and inorganic conductive particles (e.g., graphite flakes, carbon nanotubes, or graphene) results in transient dielectric composites with a surface capacitance higher than that of traditional devices based on activated carbon. These materials have the potential to revolutionize applications ranging from "green" consumer electronics to bio-resorbable medical implants-opportunities that were previously limited by the absence of suitable materials. Funding: This work was supported by the project No. CZ.02.01.01/00/22_008/0004631 “Materials and technologies for sustainable development within the Jan Amos Komensky Operational Program financed by the European Union.