1. Energy & Environment Division, Paul Scherrer Institut, Forschungstrasse 111, 5232 Villigen PSI, Switzerland
2. Laboratory for High Performance Ceramics, Empa, Swiss Federal Laboratories for Materials Testing and Research, 8600 Dübendorf, Switzerland
3. Department of Energy Conversion and Storage, Technical University of Denmark, Fysikvej 309, DK-2800 Kgs. Lyngby, Denmark
4. Laboratory of Physical Chemistry, ETH Zürich, CH-8093 Zürich, Switzerland