This study gives a short overview for current nonwoven separator materials used in nickel-metal-hydride (NiMH) and nickel-cadmium (NiCd) cells. In this context, a new material is presented, which combines the characteristics of ammonia trapping (which is synonymous to a reduced self-discharge of NiMH batteries) together with a neither environmentally nor toxicologically questionable production method, in which either free acrylic acid or fuming sulfuric acid is used. (C) 2004 Elsevier B.V. All rights reserved.