冰-水体系库仑滴定法测定LiPF6电解液中游离酸  

Determination of Free Acid in LiPF6 Electrolyte by Coulometric Titration in Ice-Water System

作　　者：申聪聪 陈田田 黄偲睿 金玲 靳素荣 蔡宏伟 SHEN Congcong;CHEN Tiantian;HUANG Cairui;JIN Ling;JIN Surong;CAI Hongwei(School of Chemistry,Chemical Engineering and Life Science,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学化学化工与生命科学学院,武汉430070

出　　处：《理化检验（化学分册）》2020年第11期1168-1172,共5页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：中央高校基本科研基金(203220004)。

摘　　要：提出了一种在冰-水体系中快速测定LiPF6电解液中游离酸含量(以氟化氢计)的方法。优化的仪器工作条件为:①反应温度为0~4℃;②支持电解质为1.0mol·L^-1 KCl溶液;③pH复合玻璃电极为指示电极,铂片电极和铂丝辅助电极为工作电极对;④恒电流为0.250~20.00mA;⑤滴定终点为pH 7.40。通过工作电极上电解产生滴定剂OH-与LiPF6电解液中的游离酸反应至滴定终点,并依据法拉第电解定律计算得到LiPF6电解液中的游离酸含量。结果表明:整个测定过程可控制在5min之内;标准曲线的线性范围为5.0~200μg,测定下限为5.0μg;加标回收率为99.7%~102%。按此方法分析了4个实际样品,测定值相对标准偏差(n=5)均小于1.0%,和非水库仑滴定法的基本一致,远优于电位滴定法的。A new method for rapid determination of the content of free acid in LiPF6electrolyte in an icewater system was proposed.The optimized instrumental working conditions were found as follows:①0-4℃in the ice-water system as reaction temperature;②1.0mol·L^-1 KCl solution as supporting electrolyte;③composite glass electrode as indicating electrode,platinum electrode and platinum wire auxiliary electrode as working electrode pairs;④constant current of 0.250-20.00mA;⑤pH 7.40as the titration end-point.The titrant OH-generated by constant current electrolysis of water was reacted with free acid in the electrolyte,and the content of free acid obtained was determined by the Faraday′s law of electrolysis.The results showed that the whole measurement process could be completed within 5minutes.The linearity range of the standard curve was kept in the range of 5.0-200μg,with lower limit of determination of 5.0μg;the recoveries found by the spiked test were ranged from 99.7%to 102%.Four actual samples were analyzed by this method,giving RSDs(n=5)of the measured values less than 1.0%,consistent with the coulometric titration in non-aqueous systems and far superior to the potentiometric titration method.

关 键 词：冰-水体系 库仑滴定法 游离酸 LiPF6电解液 

分 类 号：O657.12[理学—分析化学]