EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Design of Lithium ion conducting porous hybrid materials for the development of solid Li-battery electrolytes
Koceila MAOUACINE,Virginie HORNEBECQ,Chrystelle LEBOUIN,Luca PASQUINI
Aix-Marseille Université,France

Solid polymer electrolytes based on poly(ethylene oxid), and lithium-salt complexes are one of the promising materials for developing safe,and durable all-solid-state lithium batteries. However, the low ionic conductivity at ambient temperatur limit their practical application. The attempts to overcome the limitations of SPEs led to the generation of a new class of electrolytes in which ceramic fillers, are incorporated in PEO-Li matrix. In this context, the incorporation of mesoporous silica in the polymer matrix is attractive as its possesses interesting properties, such as its ordered structure and chemical properties.
In our work, we propose a novel approach that leads to the elaboration a porous organic-inorganic hybrid electrolyte containing a higher weight fraction of mesoporous silica than PEO. Here, the polymer-salt is entirely embedded inside the mesoporous silica matrix, offering the mechanical support to the electrolyte. Two morphologies of hybrid silica were tested, both powder and films. These were synthesized by classical (powders) and electro-assisted (films) self -assembly sol-gel method. In the first method, hybrid silica powder was synthesized and then calcined to liberate the porosity. After this, mesoporous silica was functionalized with PEO. Textural, and structural characterizations were performed by SEM,TEM,nitrogen sorption,XRD,FTIR and TGA. In the second method, hybrid silica films were deposited on glassy carbon substrates via electro-assisted self -assembly method. However, the resulting films were covered by silica particles thus reducing the pores accessibility. Several strategies were thus applied to address this problem. The convection of the sol using rotating
electrode was successful leading to particle free films. In this way, hexagonal and vertically oriented pores with a size of 3nm were obtained after template elimination. The permeability of these films was confirmed by electrochemical characterization.