Magnesium-eutectic electrolyte as a winning combination for sustainable battery

Abstract

Eutectic-Magnesium electrolytes are sparsely used electrolytes in Magnesium ion batteries. In this context, readily available less toxic precursors based eutectic electrolytes are attracting increasing interest owing to the focus of sustainable battery development. The unique benefits of magnesium such as high specific capacity, low reduction potential, and remarkable reversibility without dendrimer formation are highly advantages when compare to lithium based batteries. Developing an optimal electrolyte composition is a key area of study in the field of battery technology. With improved cell performance, stability across cycles, and general safety, we hope to reduce unwanted interfacial reactions. In this study, we examined eutectic combination of trimethylamine hydrochloride and aluminium chloride (TMA: AlCl₃ = TMA) along with magnesium perchlorate to understand ion-solvation, complexation, thermal stability, ion transport and conduction, and electrochemical stability, certain physico-chemical and electrochemical parameters were evaluated prior to assessing the cell's performance. The salient features being an ionic conductivity (σ) of 6.25×10⁻³ mS cm⁻¹ at 30 °C, remarkable performance retention with over 90 cycles of operation with the electrolyte and an impressive capacity of 90 mAh/g. The behaviour of ionic conductivity with temperature followed the Vogel-Tammann-Fulcher (VTF) equation. Moreover, the anodic stability around 2.5 V (Mg/Mg²⁺) when platinum is used as the working electrode endorses the suitability of the electrolyte for use in Rechargeable Magnesium Batteries (RMBs).The promising results of this first investigation open up new possibilities for investigating complementary pairings with the aim of improving the efficiency of magnesium-ion cells.