Electrochemical impedance spectroscopy of the LixMn2O4 interface with natural brine

Abstract

The LiMn2O4-Polypyrrole electrochemical cell has been shown to extract LiCl from natural brine at low voltage with high selectivity, low energy consumption (5?10 Wh·mol−1) and good stability. The intercalation/de-intercalation of Li+ ions in LixMn2O4 (0≤x≤ 1) has been studied by electrochemical impedance spectroscopy(EIS) at different potentials and lithium ion concentrations using a modified Randles equivalent electrical circuit for the interface of LixMn2O4 in natural brine from Salar de Olaroz (Jujuy, Argentina). The RCT exhibits twominima at potentials which correspond to x=0.25 and x= 0.75 (half filled adsorption sites) respectively and a linear lithium ion concentration dependence of (Li+)−0.5 consistent with a lithium ion transfer adsorption modelproposed by Bruce.