1. Department of Chemical Sciences, Università di Napoli “Federico II”, Compl. Univ. Monte Sant’Angelo, via Cintia 21, 80126, Napoli, Italy
2. National Reference Centre for Electrochemical Energy Storage (GISEL) - INSTM, 50121 Florence, Italy
3. Department of Physics “E. Pancini”, Università di Napoli “Federico II”, Compl. Univ. Monte Sant’Angelo, via Cintia 21, 80126, Napoli, Italy