B-ME developed the first thermoplastic composite electrode film based on bio-derived and biodegradable polyesters and carbon nano-fibers. It is metal-free, highly electrically conductive and possess good thermo-mechanical properties, a challenging combination of three features in a single product. This is the first-of-its-kind product, as, to the best of our knowledge, no thermoplastic biobased electrode film has been effectively produced and used so far. Our preliminary tests were made on 40 cm2 film electrodes, used for electrochemical measures in supercapacitors application, showing stability in acidic electrolyte over +1000 charge-discharge cycles. The application in battery and supercapacitor devices, already preliminarily demonstrated, will allow to substantially decrease the environmental impact of the current raw materials and fabrication processes. Besides sustainability these electrodes are lighter and more stable against corrosion with respect to metal counterparts.
Currently electrochemical energy storage devices rely on metal foil electrodes with aluminum or copper in the easiest configurations. When advanced devices are fabricated (e.g. bipolar plates, aqueous supercapacitors) these electrodes, beyond low sustainability, high weight (density of Al 2.7 and Cu 8.9 vs. ca. 1.5 g/cm3 for carbon composites) and supply issues, are technically challenged by the chemical reactions (e.g. corrosion, oxidation, alloying) occurring at metal interfaces. Carbon electrodes are a desired solution to all these challenges, but their fabrication can be quite complex and material-specific, and their surface inertness often causes poor electrochemical responses. This led to no or limited practical use of carbon electrode foils in commercial energy storage devices. We believe that our product will represent a breakthrough providing a versatile platform product, lightweight, bio-based and metal-free, both electrochemically stable and with an improved response.