  We present the results from an extensive atomistic molecular dynamics
simulation study of poly(ethylene oxide) (PEO) doped with various amounts of
lithium-bis(trifluoromethane)sulfonimide (LiTFSI) salt under the influence of
external electric field strengths up to $1\,$V/nm. The motivation stems from
recent experimental reports on the nonlinear response of mobilities to the
application of an electric field in such electrolyte systems and arising
speculations on field-induced alignment of the polymer chains, creating
channel-like structures that facilitate ion passage. Hence, we systematically
examine the electric field impact on the lithium coordination environment,
polymer structure as well as ionic transport properties and further present a
procedure to quantify the susceptibility of both structural and dynamical
observables to the external field. Our investigation reveals indeed a
coiled-to-stretched transformation of the PEO strands along with a concurrent
nonlinear behavior of the dynamic properties. However, from studying the
temporal response of the unperturbed electrolyte system to field application we
are able to exclude a structurally conditioned enhancement of ion transport and
surprisingly observe a slowing down. A microscopic understanding is supplied.
