Nanocomposite Polymer Electrolytes of Sodium Alginate and Montmorillonite Clay

Nanocomposite polymer electrolytes (NPEs) were synthesized using sodium alginate (Alg) and either sodium (SCa-3-Na(+))- or lithium (SCa-3-Li(+))-modified montmorillonite clays. The samples were characterized by structural, optical, and electrical properties. SCa-3-Na(+) and SCa-3-Li(+) clays’ X-ray structural analyses revealed peaks at 2θ = 7.2° and 6.7° that corresponded to the interlamellar distances of 12.3 and 12.8 Å, respectively. Alg-based NPEs X-ray diffractograms showed exfoliated structures for samples with low clay percentages. The increase of clay content promoted the formation of intercalated structures. Electrochemical Impedance Spectroscopy revealed that Alg-based NPEs with 5 wt% of SCa-3-Na(+) clay presented the highest conductivity of 1.96 × 10(−2) S/cm(2), and Alg with 10 wt% of SCa-3-Li(+) showed conductivity of 1.30 × 10(−2) S/cm(2), both measured at 70 °C. From UV-Vis spectroscopy, it was possible to infer that increasing concentration of clay promoted a decrease of the samples’ transmittance and, consequently, an increase of their reflectance.