Synthesis and Application of Magnesium Diethylphosphate for Rechargeable Magnesium Battery

Abstract

An attempt has been made to synthesize chloride free Magnesium salt. Magnesium Diethylphosphate (Mg(DEP)) by adopting a novel and economically viable chemical route. The salt is dissolved in N,N‐Dimethylformamide (DMF) and used as electrolyte for rechargeable magnesium battery (RMB). Reversible magnesium dissolution and deposition was examined in Mg‐half cell and full cell at varying potential windows. The reversible Mg intercalation and de‐intercalation at graphite cathode was analyzed by cyclic voltammetry, galvanostatic charge‐discharge and impedance analysis. Mg‐Graphite full cell has shown a discharge capacity of 70 mAh/g for 180 cycles. The cycled electrode's SEM, XRD, XPS analysis conclude the plausible Mg‐ions intercalation into the graphite. The studies could help in the development of chloride free Mg salts with potential application to serve as electrolyte for RMBs.

Unexplored Class of Eutectic Electrolytes for Rechargeable Magnesium Batteries

“…However, graphite is not usually known to store Mg 2+ ions, though the ionic radii of Mg 2+ (0.72 Å) is smaller than those of Li- and K-ions (0.76 Å for Li + and 1.38 Å for K + ) which implies that the graphite storage capacity does not depend on the ionic size of the metal ions. The rationale for this exception is extended based on the unfavorable thermodynamic interactions between the Mg ions and graphite electrode surface that do not support the intercalation. , Despite the challenges, few reports on Mg-graphite batteries successfully demonstrated the Mg-ion reversible intercalation/de-intercalation denoting the possibility of graphite as a potential cathode for RMB applications. − …”