SEPIOLITE AS AN ADDITIVE MATERIAL-CATHODE PREPARATION FOR LITHIUM SULFUR BATTERY

Abstract

Lithium-sulfur batteries have been considered as a promising next generation rechargeable energy storage system,
owing to its high theoretical capacity and specific energy density. However, several critical problems arise the wide-scale
commercial implementation of Li-S battery, namely low electrical conductivity of sulfur, dissolution of polysulfides in
electrolyte, volume expansion of sulfur during discharge [1]. To overcome these difficulties, a variety of additives were
added in to the positive electrode material. In this work, sieved Sepiolite has been chosen as an additive material to
encounter the above challenges in lithium sulfur battery.Sepiolite powders were sieved through a 200 mesh sieve (particle
size 74 microns) [2] and subjected to acid and thermal treatmentprior to use.Sepiolite is a fibrous hydrated magnesium
silicate which contains extended silicon-oxygen sheets, but the tetrahedral SiO4 groups forming these sheets are oriented to
give fibrous character of the mineral. The acid pre-activation caused restrictions in possible crystal deformation during
thermal treatment. The XRD patterns and FTIR spectra of the pure Sepiolite, sieved, acid treated and thermally treated
samples were investigated and reported.From the XRD analyses, it is concluded that the Sepiolite structure has
beencollapsed and amorphous silica was formed. The stretching of Si-O in the Si-O-Si groups of tetrahedral sheet is
observedin FT-IR spectra. From the SEM analysis, micro fibrous bundles morphology has been observed.