Novel infiltration method of membranes over activated carbons electrodes

A novel method to modify activated carbons electrodes through addiction of selective ion exchange membrane (IEM) is presented. Nowadays the preferred method to modify an electrode in an electric double layer supercapacitor is to apply a stand-alone membrane in proximity of the electrode itself. This technique produces some drawbacks in terms of dimensions of the device, increase of the internal series resistance and reduction of the total capacitance. With the present method it is possible to use the membrane with a conformal contact with the electrode or directly in the production of the slurry. In particular the first approach studied consists into melting the membrane and casting and drying it under vacuum over activated carbons. This drying process, is performed in a glass oven B-585 from BÜCHI. In this way it is possible to reduce internal resistance of the device, providing good ion selectivity and maintaining a high capacitance. The second approach consists in exploiting the IEM as polymeric functional binder inside the slurry. It is possible to exploit the long chains of ion exchange polymers to bind activated carbons together and onto the substrate. This strategy allows the substitution of common binders like PVDF, with several benefits in terms of reduced electrical resistance, tunable surface charge of the electrodes, reduced cost and increased sustainability.