Novos compósitos de POMA com LLZO dopados com Sr e Mg e seu potencial para aplicação em eletrólitos de estado sólido

Abstract

Solid-state electrolytes have been widely applied to optimize the performance of lithium-ion batteries. In this context, ceramic-polymeric composites are increasingly being developed and analyzed through various characterization techniques, aiming to explore the great potential of these materials as electrolytes in solid-state batteries. In the present work, ceramic-polymeric composites based on Li7La3Zr2O12 doped with strontium (Sr) and magnesium (Mg) (LLZO-SM), with the addition of poly(o-methoxyaniline) (POMA), were produced and characterized. The influence of incorporating different POMA contents (1%, 5%, 20%, and 50%) on the composite properties was evaluated. Both materials were homogenized using the sonochemical method and shaped into pellets by mechanical pressing, without further heat treatment. The composites were characterized in terms of their structural, thermal, morphological, and electrical properties. X-ray diffraction (XRD) results showed changes in the crystalline phases of the composites, particularly with the addition of 20% POMA to the LLZO-SM matrix. Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the presence of characteristic functional groups of POMA and LLZO-SM, indicating good interaction between the composite's constituent materials. Thermogravimetric analysis demonstrated thermal stability, especially for the composites containing 1%, 5%, and 20% POMA. Scanning electron microscopy (SEM) images revealed gradual changes in the composite morphology as the POMA concentration increased. The results obtained through complex impedance spectroscopy (CIS) characterization demonstrated that the formation of the POMA/LLZO-SM composite provided significant improvements in electrical conductivity and a substantial reduction in the materials' impedance. The sample with 20% POMA proved to be the most suitable for applications requiring lower electrical resistance. This sample exhibited an excellent combination of structural, thermal, and morphological properties within the analyzed parameters, positioning it as a promising candidate for solid-state electrolytes in lithium-ion batteries, as well as for future studies in the same field of technological application.

Key-words: LLZO-SM, POMA, composites, electrolytes, batteries.