1. CEA Marcoule, DEN/DRCP/SCPS, 30207 Bagnols sur Cèze, France, Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospect, 119991 Moscow, Russian Federation, Laboratoire de Chimie du Solide et Matériaux, UMR CNRS 6226, Université de Rennes 1, Avenue du Général Leclerc, 35042 Rennes, France, IPN Orsay, Université Paris XI Orsay, 91405 Orsay, France, and Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720