1. Laboratory of Materials for Renewable Energy (LMER), Institute of Chemical Sciences and Engineering (ISIC), Basic Science Faculty (SB), École polytechnique fédérale de Lausanne (EPFL), Valais/Wallis, Energypolis,
Rue de l'Industrie 17, CP 440, CH-1951 Sion, Switzerland; EMPA Materials Science & Technology, Dübendorf, Switzerland. andreas.zuettel@epfl.ch
2. Laboratory of Materials for Renewable Energy (LMER), Institute of Chemical Sciences and Engineering (ISIC), Basic Science Faculty (SB), École polytechnique fédérale de Lausanne (EPFL), Valais/Wallis, Energypolis, Rue de l'Industrie 17, CP 440, CH-1951 Sion, Switzerland; EMPA Materials Science & Technology, Dübendorf, Switzerland
3. EMPA Materials Science & Technology, Dübendorf, Switzerland