1. J. Heyrovský Institute of Physical Chemistry, v.v.i., Academy of Sciences of the Czech Republic, Dolejškova 3, CZ-18223 Prague 8, Czech Republic
2. High Power Lithium, SA, PSE-B, Ecublens, CH-1015 Lausanne, Switzerland
3. Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany
4. Laboratory of Photonics and Interfaces, EPFL, Ecublens, CH-1015 Lausanne, Switzerland