1. Department of Battery Technology Institute for Energy Technology (IFE) Instituttveien 18 2007 Kjeller Norway
2. Present address: SINTEF Industry Forskningsveien 1 0373 Oslo Norway
3. SINTEF Materials Physics Forskningsveien 1 0373 Oslo Norway
4. Present address: Cenate AS Rakkestadveien 1 1814 Askim Norway
5. Centre for Materials Science and Nanotechnology (SMN) Department of Chemistry University of Oslo P.O. Box 1033, Blindern 0315 Oslo Norway