锂离子动力电池用二氟磷酸锂的制备研究
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摘要
使用碳酸锂与六氟磷酸锂电解液接触反应以制备二氟磷酸锂,对比考察了反应温度、原料电解液浓度对实验的影响,采用核磁共振对所制备目标产物进行定性研究,使用离子色谱对所制备二氟磷酸锂电解液进行了阴离子检测,并进一步考察了二氟磷酸锂电解液的稳定性。结果表明,45℃下所制备电解液中杂质阴离子最少;选取质量分数为15%的六氟磷酸锂/碳酸二甲酯(LiPF6/DMC)电解液可兼顾较好的反应速率及整体时间效益;二氟磷酸锂/六氟磷酸锂/碳酸二甲酯(LiPO_2F_2/LiPF6/DMC)电解液在保存过程中一定要严格隔绝水分,以保证电解液中有效成分含量的稳定性。
Lithium difluorophosphate was prepared by lithium carbonate and lithium hexafluorophosphate electrolyte.The effects of reaction temperature and concentration of raw electrolyte on the experiment were compared.Qualitatively,the target product was identified by nuclear magnetic resonance.In addition,anion detection of lithium difluorophosphate electrolyte and further investigation of the stability of lithium difluorophosphate electrolyte were made.The results showed that,the impurity anion of the electrolyte prepared at 45 ℃ was the least; Selecting 15% LiPF6(mass fraction)/DMC electrolyte can give consideration to the better reaction rate and overall time efficiency;Furthermore,LiPO_2 F_2/LiPF6/DMC electrolyte must be strictly isolated from water in the preservation process to ensure the stability of the active ingredient content in the electrolyte.
Lithium difluorophosphate was prepared by lithium carbonate and lithium hexafluorophosphate electrolyte.The effects of reaction temperature and concentration of raw electrolyte on the experiment were compared.Qualitatively,the target product was identified by nuclear magnetic resonance.In addition,anion detection of lithium difluorophosphate electrolyte and further investigation of the stability of lithium difluorophosphate electrolyte were made.The results showed that,the impurity anion of the electrolyte prepared at 45 ℃ was the least; Selecting 15% LiPF6(mass fraction)/DMC electrolyte can give consideration to the better reaction rate and overall time efficiency;Furthermore,LiPO_2 F_2/LiPF6/DMC electrolyte must be strictly isolated from water in the preservation process to ensure the stability of the active ingredient content in the electrolyte.
引文
[1]大下竜司,藤本正久,能间俊之.非水系电解液二次电池:日本,特开平11-67270[P].1999-03-09.
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[5] Sharabi R,Fridman K,Aurbach D,et al.Cycling performance of LiCoPO4cathodes:reasons for capacity fading and effect of the electrolyte composition[J].Journal of Applied Physics,2013,55(5):134-142.
[6] Markevich E,Sharabi R,Gottlieb H,et al.Reasons for capacity fading of LiCoPO4cathoder in LiPF6containing electrolyte solutions[J].Electrochemistry Communications,2012,15:22-25.
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[2]吴宇平,戴晓兵,马军旗,等.锂离子电池—应用与实践[M].北京:化学工业出版社,2004:222-228.
[3] Plakhotnyk A V,Ernst L,Schmutzler R,et al.Hydrolysis in the system LiPF6—propylene carbonate—dimethyl carbonate—H2O[J].Journal of Fluorine Chemistry,2005,126(1):27-31.
[4] Yang Li,Zhang Hanjun,Driscoll P F,et al.Six-membered-ring malonatoborate-based lithium salts as electrolytes for lithium ion batteries[D].Kingston:University of Rhode Island,2014.
[5] Sharabi R,Fridman K,Aurbach D,et al.Cycling performance of LiCoPO4cathodes:reasons for capacity fading and effect of the electrolyte composition[J].Journal of Applied Physics,2013,55(5):134-142.
[6] Markevich E,Sharabi R,Gottlieb H,et al.Reasons for capacity fading of LiCoPO4cathoder in LiPF6containing electrolyte solutions[J].Electrochemistry Communications,2012,15:22-25.
[7] Cavell R G.The reaction of thiophosphoryl fluoride with dimethylamine and some properties of the dimethylaminothiophosphoryl fluorides[J].Canadian Journal of Chemistry,1968,46:613.