Polymer Electrolytes in Strong External Electric Fields: Modification of Structure and Dynamics

Abstract

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 impact of electric field 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 achieved.

[Retracted] Translation and Expression of Professional Terms of Public Emergencies in External Reports

“…During this period, CCTV news channel's "weekly quality report" column broadcast the special investigation news "secrets in the capsule" to expose the event for the first time, which was reprinted and tracked by many domestic news websites. The "poison capsule incident" instantly became a hot spot of media focus [8,9]. Within 30 days after the "poison capsule incident" was exposed on April 15, 2020, the number of news reports on the "poison capsule incident" by major domestic media was about 107790 (including reprinted news).…”

Effect of different soluble salt ions on deformation of desulfurization gypsum in high humidity environment: a statistically designed experimental analysis method

“…Compared with the sagging deflection of + Mg , 2 the sagging deflection of + K + + Mg 2 decreased from 1.933 mm to 0.605 mm, and the inhibition degree was 69.4%. This is because + K as a strong electrolyte ion can effectively promote the growth of whiskers along the c-axis, so that the aspect ratio increases, and the whiskers crystallize well (Miyi et al 2015, Wettstein et al 2021. This whisker with a large aspect ratio is interspersed between gypsum crystals, which can increase the lap point between crystals, improve the energy required for the ring-breaking process, and then reduce the sagging deflection of desulfurization gypsum board.…”