Artículos de revistas
Surface studies of lithium-oxygen redox reactions over HOPG
Fecha
2016-04Registro en:
Marchini, Florencia; Herrera, Santiago Esteban; Calvo, Ernesto Julio; Williams, Federico José; Surface studies of lithium-oxygen redox reactions over HOPG; Elsevier Science; Surface Science; 646; 4-2016; 154-159
0039-6028
CONICET Digital
CONICET
Autor
Marchini, Florencia
Herrera, Santiago Esteban
Calvo, Ernesto Julio
Williams, Federico José
Resumen
The O2/Li2O2 electrode reaction has been studied on low surface area HOPG electrodes in 0.1 M LiPF6 in dimethyl sulfoxide (DMSO) electrolyte. Studies were performed using electrochemical cells coupled to a XPS spectrometer and to an AFM microscope. AFM images after electrochemical treatment at cathodic potentials exhibited 20 to 100 nm in height features, whereas anodic treatment showed a thin film of about 1 nm thickness deposited over the HOPG electrode. XPS spectra after electrochemical treatment showed surface species due to DMSO and LiPF6 decomposition. These findings indicate the high reactivity of oxygen reduction products towards the electrolyte and the solvent. The unwanted deposits formed under electrochemical operation cannot be completely eliminated from the surface even after applying high anodic potentials. This highlights the known loss of capacity of Li-air batteries, issue that must be overcome for successful applications.