Journal of Power Sources, Vol.319, 202-209, 2016
Ab initio investigation of the oxygen reduction reaction activity on noble metal (Pt, Au, Pd), Pt3M (M = Fe, Co, Ni, Cu) and Pd3M (M = Fe, Co, Ni, Cu) alloy surfaces, for Li-O-2 cells
First principles, density functional theory (DFT) modelling of the oxygen reduction reaction (ORR) on noble metal (Pt, Au, Pd), Pt3M (M = Fe, Co, Ni, Cu) and Pd3M (M = Fe, Co, Ni, Cu) alloy surfaces, was carried out. Periodic models of close-packed (111) surfaces were constructed, their geometry was optimized and the most stable geometric surface configuration was identified. The correlation between the intermediate species binding energy and the favored reaction pathway from amongst 1e(-), 2e(-), and 4e(-) mechanisms were studied by calculating the binding energies of a 1/4 monolayer of O, O-2, LiO, LiO2, Li2O2, and Li2O on various sites and orientations. The reaction free energies (Delta G(rxn)) were calculated and used to compute the catalytic activity of the surfaces using molecular kinetics theory. Plots of the catalytic activity vs. Oxygen binding energy (E-Binding (o)) showed a typical "volcano" profile. The insights gained from this study can be used to guide the choice of cathode catalysts in Li-O-2 cells. (C) 2016 Elsevier B.V. All rights reserved.
Keywords:Lithium-oxygen cell;Density functional theory;Catalytic activity;Li2O2 nucleation;Surface passivation