二氟磷酸锂的制备及电化学性能研究
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摘要
为探究二氟磷酸锂(LiPO_2F_2)的制备方法及其对锂离子电池性能的影响,尝试以六氟磷酸锂(LiPF_6)和磷酸锂(Li_3PO_4)为原料,采用固相法制备LiPO_2F_2,通过核磁共振(NMR)、X射线衍射(XRD)、离子色谱(IC)对材料做了物相研究和定性检测;通过充放电测试、循环伏安(CV)、电化学阻抗(EIS)研究了材料对电池性能的影响。测试结果表明,以LiPF6及Li_3PO_4为原料可制得LiPO_2F_2,LiPO_2F_2作为添加剂加入电解液中使得电池电极极化现象有所减弱,电池正负极材料的成膜电阻明显减小,同时提高了电池的循环稳定性及高温存储性能。
In order to explore the preparation method of lithium difluorophosphate(LiPO_2F_2) and its effects on the perfor mance of lithium ion batteries,LiPO_2F_2 was prepared by solid phase method using lithium hexafluorophosphate(LiPF_6) and lithium phosphate(Li_3PO_4) as raw materials.The material was then subjected to phase analysis and qualitative detection by nuclear magnetic resonance(NMR),X-ray diffraction(XRD) and ion chromatography(IC),and the effects of materials on battery performance were investigated by charge and discharge tests,cyclic voltammetry(CV) and electrochemical impedance(EIS).The results showed that li PO_2F_2 could be obtained by using LiPF_6 and Li_3PO_4 as raw materials,the polarization of the battery electrode was weakened by adding LiPO_2F_2 as an additive to the electrolyte,the film-forming resistance of the positive and negative materials of the battery was significantly reduced,and the cycle stability and high-temperature storage performance of the battery were improved.
In order to explore the preparation method of lithium difluorophosphate(LiPO_2F_2) and its effects on the perfor mance of lithium ion batteries,LiPO_2F_2 was prepared by solid phase method using lithium hexafluorophosphate(LiPF_6) and lithium phosphate(Li_3PO_4) as raw materials.The material was then subjected to phase analysis and qualitative detection by nuclear magnetic resonance(NMR),X-ray diffraction(XRD) and ion chromatography(IC),and the effects of materials on battery performance were investigated by charge and discharge tests,cyclic voltammetry(CV) and electrochemical impedance(EIS).The results showed that li PO_2F_2 could be obtained by using LiPF_6 and Li_3PO_4 as raw materials,the polarization of the battery electrode was weakened by adding LiPO_2F_2 as an additive to the electrolyte,the film-forming resistance of the positive and negative materials of the battery was significantly reduced,and the cycle stability and high-temperature storage performance of the battery were improved.
引文
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[2]井原将之,胁野真也,漥田忠彦.电解液和二次电池:中国,101783412A[P].2010-07-21.
[3]韩秀熙,金荣圭,金炳和.可再充电锂电池:中国,103208647A[P].2013-07-17.
[4]Plakhotnyk A V,Ernst L,Schmutzler R.Hydrolysis in the system LiPF6-propylene carbonate-dimethyl carbonate-H2O[J].Journal of Fluorine Chemistry,2005,126(1):27-31.
[5]Sharabi R,Fridman K,Aurbach D,et al.Cycling performance of LiCoPO4 cathodes:Reasons for capacity fading and effect of the electrolyte[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 thiophosphorylfluoride with dimethylamine and some properties of the dimethylaminothiophosphoryl fluorides[J].Canadian Journal of Chemistry,1968,46:613.
[8]麦永津,闫晓丹,谢波,等.腈基功能化有机硅基电解液在4.4V钴酸锂/石墨锂离子电池中的性能研究[J].中国科学:化学,2014,44(8):1325-1331.