Main problems in the field of electromobility are the high price and the low capacitance of rechargeable batteries. Important elements of such batteries are aluminium collector foils and their interfaces towards carbon based electrode material. The ohmic resistance of the interface should be minimal. But in air Aluminium generally is oxidized. This thin oxide layer increases the ohmic resistance. Because of this often aluminium collectors are chemically pre-treated to minimise the negative effect of the oxide layer. This chemical step is not only not eco-friendly but also expensive. With regard to battery production this chemical pre-treatment is an important cost factor. The generally applied chemical pre-treatment of aluminium collector foils can be replaced by a more environment-friendly process using plasma treatment. The basic idea is to embed carbon based microparticles into the surface of the aluminium foil. The carbon particles penetrate the native aluminium oxide layer partly the oxide layer is eliminated. In this way the contact resistance of the foil is reduced. Such carbon embedding is effected by a plasma discharge. In one embodiment the microparticles are dispersed in an inert gas. A nozzle comprises an electrode an aerosol flow is directed through the nozzle onto the foil a dielectric barrier discharge is initiated in a manner that a cold plasma is effective at the surface of the foil. In another embodiment a porous layer containing carbon microparticles is applied to the aluminium foil. In a next step a plasma discharge is initiated which is directed to the surface of the foil. The plasma effects an embedding of the carbon particles and in part an elimination of the native oxide layer. Applications: Lithium-Ion-batteries
Eco-friendly