CONICET | Buscador de Institutos y Recursos Humanos

In Argentine many researchers are focused on preventing some of the problems associated with lithium-sulfur technology. In this work, we used a polymeric and a ceramic coating on the separator as a strategy to avoid dendrites formation. On one hand, the polymeric coating consisted in a montmorillonite (MMT)/polyaniline (PANI) composite. PANI has already been widely used in many fields due to its low density, high electronic conductivity, ease of preparation and unique physical/chemical properties. However, PANI prepared in the absence of a support is usually powder and difficult to serve as an interlayer material alone. In that sense, montmorillonite, a T:O:T phyllosilicate was used as a matrix to polymerize aniline due to its colloidal size, great cation exchange capacity (80-100 mmol/100g), variable and flexible interlayer spacing, good mechanical properties and because it is wettable and permeable to polar solvents, such as alcoholic and ether electrolytes. On the other hand, the ceramic coating was formed by monoclinic lithium zirconate (m-Li2ZrO3) which is an excellent Li+ conductor. In its structure, Li+ are located among the ZrO32− layers and offer a three-dimensional tunnel for Li+ diffusion. This feature, in addition to its thermodynamic stability against Li and chemical inertia in common nonaqueous electrolytes makes this material commonly used as coating to suppress the dissolution of cathode material, such as spinel LiMn2O4 or LiNi0.5Mn1.5O4 at high charge potential. PANI/MMT composite was obtained by chemical polymerization whereas a ratio PANI/MMT = 12.4/87.6 (w/w) was used. The powder was characterized by x-ray diffraction (XRD), thermal analyses, zeta potential measurements, and infrared and x-ray photoelectron spectroscopies (FTIR and XPS, respectively).