关键词: 乙烯硫脲, 格氏试剂, 电解液, 可充镁电池

Abstract: Three kinds of ethylenethiourea-Grignard reagent/THF electrolytes were prepared by reacting ethylenethiourea with different Grignard reagents such as EtMgBr/THF, PhMgBr/THF and PhMgCl/THF. Cyclic voltammetry tests on Pt disk electrode show that the electrolytes have good performance of magnesium deposition-dissolution as Grignard reagents and higher anodic stabilities than Grignard reagents. The oxidative decomposition potential of ethylenethiourea-PhMgBr/THF on Pt electrode can reach 2.3 V (vs. Mg/Mg²⁺). The conductivity of ethylenethiourea-PhMgBr/THF electrolyte initially increases and then decreases with the increase of the concentration and reaches to the highest value of 615 μS·cm^-1 at 0.9 mol·L^-1. The comparison in cyclic voltammograms of 0.9 mol·L^-1 ethlenethiourea-PhMgBr/THF electrolyte on Pt, Ni, Cu and Al electrodes demonstrates that the oxidative decomposition potential on Ni electrode is the highest (2.4 V (vs. Mg/Mg²⁺)). Constant-current discharge and charge tests of coin cells further show that the magnesium deposition-dissolution potential on Ni substrate is low and the stable cycle efficiency can reach 92%. For ethlenethiourea-PhMgBr/THF electrolyte, nickel is suitable to be used as a practical current collector.

Key words: ethylenethiourea, Grignard reagent, electrolytes, rechargeable magnesium batteries