TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The concentration of the particles increases, and the pore density and/or the pore size decrease, along the preferred direction. The concentration gradient, and/or the gradient of the pore density and/or pore size, is step gradient. The storage element comprises a marginalized metal layer (30), where the preferred direction forms a surface normal. The marginalized metal layer surrounds both sides of ceramic layers (28), which are at least largely free of pores and particles. The ceramic particles comprise redox-inert material, preferably aluminum oxide, magnesium oxide or zirconium dioxide, and exhibit a median particle size of less than 1 mu m. The particles comprise iron, nickel or manganese and/or the respective oxides, and exhibit a median particle size of 1-10 mu m. The first slurry comprises metal and/or metal oxide (50 vol.%) and pore former (10 vol.%), the second slurry comprises metal and/or metal oxide (35 vol.%) and pore former (20 vol.%), and the third slurry comprises metal and/or metal oxide (20 vol.%) and pore former (30 vol.%), where the remaining of the slurry is formed respectively of ceramic particles. Preferred Method: The method comprises: producing a first green film on a support by film casting the first slurry, and at least one further green film on a support by film casting the further slurry, for forming the green body; removing the respective supports; stacking green film sections to green body; laminating; and debinding, where a first partial region of the green body is formed by stacking films sections of the first green film, and at least one further partial region of the green body is formed by stacking film sections of the second green film. A total of three green films are produced from respectively assigned slurries. The method further comprises stacking several film sections of the first green film, several film sections of the second green film and several film sections of the third green film for forming the green body; additionally providing a ceramic slurry having particle components of ceramic particles, and a metal slurry having particle components of particles made from the metal; producing corresponding green films from the slurries; and additionally stacking several film sections of the green film produced from the ceramic slurry, several film sections of the green film produced from the metal slurry, and several film sections of the green film produced from the ceramic slurry on the green body after forming the green body from the first- and the further green film.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The pore formers comprise natural fibers, carbon particles or cellulose particles having a median particle size of 10-50 mu m. EXAMPLE - No suitable example given.