On the dynamics of PEO-NaI polymer electrolytes

• Published in: Electrochimica acta 2001-03, Vol.46 (10), p.1717-1721
• Main Authors: van Zon, A., Mos, B., Verkerk, P., de Leeuw, S.W.
• Format: Article
• Language: English
• Subjects: Applied sciences; Electrical, magnetic and optical properties; Exact sciences and technology; Molecular dynamics; Neutron scattering; Organic polymers; Physicochemistry of polymers; Polymer electrolytes; Properties and characterization; Structural relaxation
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/S0013-4686(00)00776-3

We present the results of a detailed molecular dynamics study of poly(ethylene-oxide) (PEO) NaI polymer electrolytes. We focus on the influence of the salt on the dynamics of the polymer segments. This is done by calculating the mean square displacements of the CH 2 groups and comparing the corresponding self-part of the intermediate scattering function with neutron spin-echo experiments. Three different systems are studied: pure PEO, PEO-NaI with reduced ion charges, and PEO-NaI with harmonic springs between the O atoms and Na ions. Simulations of pure PEO are in good agreement with the experimental results, indicating the validity of the PEO model. In the polymer electrolyte, a slowing down is observed in both the PEO-NaI models. Adding harmonic springs between Na and O results in a better agreement with neutron spin-echo experiments. It also affects the k dependence of the relaxation times of F( k, t), changing from ν=3.3 to ν=4.0 ( τ∼ k − ν ). This is also observed in experiments.