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Article Dans Une Revue Macromolecules Année : 2016

Structure and Ionic Conductivity of Polystyrene- block -poly(ethylene oxide) Electrolytes in the High Salt Concentration Limit

Mahati Chintapalli
  • Fonction : Auteur
Thao Le
  • Fonction : Auteur
Naveen Venkatesan
  • Fonction : Auteur
Nikolaus Mackay
  • Fonction : Auteur
Adriana Rojas
  • Fonction : Auteur
Jacob Thelen
  • Fonction : Auteur
X. Chelsea Chen
  • Fonction : Auteur
Nitash Balsara
  • Fonction : Auteur

Résumé

We explore the relationship between the morphology and ionic conductivity of block copolymer electrolytes over a wide range of salt concentrations for the system polystyrene-block-poly(ethylene oxide) (PS-b-PEO, SEO) mixed with lithium bis(trifluoromethanesulfonyl)imide salt (LiTFSI). Two SEO polymers were studied, SEO(16–16) and SEO(4.9–5.5), over the salt concentration range r = 0.03–0.55. The numbers x and y in SEO(x–y) are the molecular weights of the blocks in kg mol–1, and the r value is the molar ratio of salt to ethylene oxide moieties. Small-angle X-ray scattering was used to characterize morphology and grain size at 120 °C, differential scanning calorimetry was used to study the crystallinity and the glass transition temperature of the PEO-rich microphase, and ac impedance spectroscopy was used to measure ionic conductivity as a function of temperature. The most surprising observation of our study is that ionic conductivity in the concentration regime 0.11 ≤ r ≤ 0.21 increases in SEO electrolytes but decreases in PEO electrolytes. The maximum in ionic conductivity with salt concentration occurs at about twice the salt concentration in SEO (r = 0.21) as in PEO (r = 0.11). We propose that these observations are due to the effect of salt concentration on the grain structure in SEO electrolytes.

Dates et versions

hal-02324390 , version 1 (21-10-2019)

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Mahati Chintapalli, Thao Le, Naveen Venkatesan, Nikolaus Mackay, Adriana Rojas, et al.. Structure and Ionic Conductivity of Polystyrene- block -poly(ethylene oxide) Electrolytes in the High Salt Concentration Limit. Macromolecules, 2016, 49 (5), pp.1770-1780. ⟨10.1021/acs.macromol.5b02620⟩. ⟨hal-02324390⟩
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