A method for the preparation of highly porous metallic battery electrode structures by the action of pressure alone without the application of heat is described in which the surface of the powders used for the compact is cleaned by the action of mild acids prior and during the pressing operation. In a first modification, a mixture of metallic powder, a powdered nonreactive pore-forming agent and a mild acid are pressed to form a porous structure. In a second modification, a mixture of metallic powder and a powdered slightly soluble mild acid are pressed to form a porous structure. In the two modifications the pore former is removed after the pressing operation.