Síntese de eletrólitos poliméricos baseados em blendas poliméricas de POE/NaAlg modificadas com LiClO4

Abstract

The study of salt-modified polymer blends has been an alternative in the research of new materials. Modified blends can exhibit better mechanical, thermal and electrical properties compared to pure polymers and blends, in addition to low acquisition cost. These lithium salt-modified polymer systems have been applied as electrolytes in electrochemical devices. The present investigation involved the study of membranes based on poly (ethylene oxide) (PEO) and sodium alginate (NaAlg) blends (PEO:NaAlg) modified with lithium perchlorate (LiClO4), obtaining solid polymer electrolytes (PEO:NaAlg:LiClO4) with considereable ionic conductivity for these systems, at ambient temperature. Structural, chemical, morphological and electrical characterization was conducted by X-ray diffraction (XRD), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry/derivative thermogravimetry (TG/DTG) and electrochemical impedance spectroscopy (EIS). The data obtained by DSC, FTIR, XRD and SEM showed that total system crystallinity decreased as a function of blend composition, declining proportionately with an increase in the NaAlg ratio in the membranes. Moreover, the data obtained by ATR-FTIR revealed physical interaction between the polymers. Electrochemical impedance characterization demonstrated that the electrical behavior of the membranes at different polymer proportions changed in relation to the different polymer ratios. The addition of salt resulted in a slight variation in their electrical properties. Of the different systems studied, the P20 membrane exhibited the best ionic conductivity, with = 9.45x10-6 S.cm-1, and at the same proportion, after adding salt (P20S), it changed to = 2.45x10-5 S.cm-1. Thus, the best ionic conductivity of all the membranes analyzed was observed in P20S.