These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: What can we learn from ionic conductivity measurements in polymer electrolytes? A case study on poly(ethylene oxide) (PEO)-NaI and PEO-LiTFSI.
    Author: Stolwijk NA, Wiencierz M, Heddier C, Kösters J.
    Journal: J Phys Chem B; 2012 Mar 15; 116(10):3065-74. PubMed ID: 22316082.
    Abstract:
    We explore in detail what information on ionic diffusivity and ion pairing can be exclusively gained from combining accurate direct-current conductivity data in polymer electrolytes with a novel evaluation model. The study was performed on two prototype systems based on poly(ethylene oxide) (PEO) with known disparate ion-association properties, which are due to the dissimilar salt components being either sodium iodide (NaI) or lithium bis(trifluoromethane-sulfonyl)imide (LiN(CF(3)SO(2))(2) or LiTFSI). The temperature dependence of the conductivity can be described by an extended Vogel-Tammann-Fulcher (VTF) equation, which involves a Boltzmann factor containing the pair-formation enthalpy ΔH(p). We find a distinct increase of the positive ΔH(p) values with decreasing salt concentration and similarly clear trends for the pertinent VTF parameters. The analysis further reveals that PEO-NaI combines a high pair fraction with a high diffusivity of the I(-) ion. By contrast, PEO-LiTFSI appears to be characterized by a low ion-pairing tendency and a relatively low mobility of the bulky TFSI(-) ion. The observed marked differences between PEO-NaI and PEO-LiTFSI complexes of homologous composition are most pronounced at high temperatures and low salt concentrations.
    [Abstract] [Full Text] [Related] [New Search]