水对AlCl3-BMIC离子液体电沉积铝的影响

采用循环伏安和线性扫描伏安法研究水对摩尔比为2:1的AlCl3-BMIC离子液体电化学性质的影响。结果表明:随着含水量的增加,铝的还原峰电流密度减小,阴极和阳极极化过电位增加,槽电压不断升高。当离子液体含水量低于1.39 mol/L时,电流效率稳定在94%~95%;继续增加含水量到1.67 mol/L时,电流效率从94%下降到64.7%。当离子液体含水量低于1.39 mol/L时,沉积层变得更致密;当含水量增加到1.67 mol/L时,沉积层变得疏松。离子液体含水量为1.39 mol/L时,铝的纯度超过99.9%。

Effect of water on electrodeposition of aluminum from AlCl3-BMIC ionic liquid

The effect of water on electrochemical characteristics of AlCl3-BMIC ionic liquid with molar ratio of 2:1 was investigated by cyclic voltammetry and linear sweep voltammetry.The results show that the cathodic peak current density decreases,the overpotential values of cathode and anode increase and the cell voltage increases with water concentration increasing in the ionic liquid.Furthermore,the cell voltage,current efficiency and surface morphology of aluminum electrodeposits are affected by amount of water in ionic liquid.The current efficiency is various in the range from 94% to 95% when the water concentration is below 1.39 mol/L,while it decreases sharply from 94% to 64.7% when the water concentration is increased to 1.67 mol/L.The deposit layer becomes more compact when the water concentration of ionic liquid is below 1.39 mol/L,but it becomes loosen when the water concentration is increased to 1.67 mol/L.The purity of aluminum deposit is over 99.9% when the water concentration is 1.39 mol/L.