1. Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama 226-8503, Japan, Centre for Materials Science and Nanotechnology, Department of Chemistry, University of Oslo, Blindern N-0315 Oslo, Norway, Laboratory of Inorganic and Analytical Chemistry, Helsinki University of Technology, FI-02150 Espoo, Finland, Institute for Energy Technology, N-2027 Kjeller, Norway, and Texas Materials Institute, ETC 9.102, The University of Texas at Austin, Austin, Texas 78712