乙烯硫脲-格氏试剂/THF电解液镁沉积-溶出性能

Magnesium Deposition-Dissolution Performance of Ethylenethiourea-Grignard Reagent/THF Electrolytes

将乙烯硫脲与不同格氏试剂EtMgBr/THF、PhMgBr/THF、PhMgCl/THF反应制得了3种乙烯硫脲-格氏试剂/THF电解液.通过循环伏安测试了在Pt电极上的镁沉积-溶出性能.结果表明,形成的乙烯硫脲-格氏试剂/THF电解液未改变电解液的镁沉积-溶出性能,却拓宽了其电化学窗口.如乙烯硫脲-PhMgBr/THF溶液的氧化分解电位可达2.3 V(vs.Mg/Mg2+),该电解液的电导率随溶液溶度增大先升后降,0.9 mol·L-1时其电导率最高,可达615μS·cm-1.比较乙烯硫脲-PhMgBr/THF在Pt、Ni、Cu和Al四种金属电极的电化学性能,发现在Ni电极的氧化分解电位最高,可达2.4 V(vs.Mg/Mg2+),且具有良好的镁沉积-溶出性能.CR2016扣式电池的循环测试表明,Ni基底上的镁沉积-溶出电位较低,其循环效率可达到92%,适宜作为实用电池的集流体.

Three kinds of ethylenethiourea-Grignard reagent/THF electrolytes were prepared by reacting ethylenethiourea with different Grignard reagents such as EtMgBr/THF, PhMgBr/THF and PhMgC1/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/Mg^2＋）. 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 txS μm^-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.