  In this paper for the first time we report the results of molecular dynamics
simulation of electrode/electrolyte interface of Li-O2 cathode under potential
close to experimental values in 1M dimethyl sulfoxide (DMSO) solution of LiPF6
salt. Electric potential profiles, solvent structuring near the electrode
surface and salt ions distributions are presented and discussed here as well as
potentials of mean force (PMF) of oxygen and its reduction products. The latter
would be of a great use for the future theoretical studies of reaction kinetics
as PMF being essentially the work term is a required input for the reaction
rate constant estimations. Electrode/electrolyte interface under the realistic
potential effectively push oxygen anions out of the reaction layer that makes
second reduction of superoxide anion hardly probable. Thus the main cause of
the passivation should be the lithium superoxide presence near the electrode
surface. The way to suppress the passivation is the shifting of equilibrium
O_2^- + Li_+ <-> LiO_2 to the side of separately solvated ions, for example by
using solvents resulting in lower free energy of the ions. This conclusion is
in agreement with the hypothesis stating that high donor number solvents lead
to dominantly solution Li2O2 growth and significantly higher cell discharge
capacities.
