杂质对金属锂电解过程的影响

Effects of Impurities on Electrolysis Process of Lithium Metal

以50%KCl-50%LiCl体系为熔盐电解质体系,研究杂质包括NaCl、CaCl2、MgCl2、FeCl3、Li2SO4在420℃下对电解过程的影响。结果表明:NaCl、CaCl2、MgCl2优先于金属锂在阴极析出钠、镁、钙,进入金属锂产品中,同时引起金属锂聚集性变差,降低电流效率和锂收率;FeCl3在阴极上析出海绵铁形成钝化膜,影响电解过程;Li2SO4在阴极上与金属锂发生氧化还原反应,消耗金属锂生成Li2O和Li2S,降低电流效率和锂收率。

Effects of impurities of NaCl,CaCl2,MgCl2,FeCl3 and Li2SO4 in electrolysis process were studied at 420℃with 50%KCl-50%LiCl as molten salt electrolyte system.The results show that deposition of sodium,magnesium and calcium is precipitated prior to lithium and entered into lithium metal cathode products,causing poor aggregation of lithium metal and reducing current efficiency and lithium yield.Impurity FeCl3 is preferentially reduced to sponge iron resulting in cathode passivation then affects electrolysis process.Li2SO4 reacts with lithium metal by oxidation and reduction,consuming lithium metal to produce Li2O and Li2S,and reducing current efficiency and lithium yield.