一种用于磷酸铁锂电极的水性黏结剂制备与性能研究  

Study on preparation and performance of aqueous binder for lithium iron phosphate electrodes in lithium-ion battery

作　　者：曹佳宁 高翔[1,2] 罗英武 苏荣欣[3] CAO Jianing;GAO Xiang;LUO Yingwu;SU Rongxin(State Key Laboratory of Chemical Engineering,College of Chemical and Biological Engineering,Zhejiang University,Hangzhou 310027,Zhejiang,China;Institute of Zhejiang University-Quzhou,Quzhou 324000,Zhejiang,China;State Key Laboratory of Chemical Engineering,School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China)

机构地区：[1]化学工程联合国家重点实验室,浙江大学化学工程与生物工程学院,浙江杭州310027 [2]浙江大学衢州研究院,浙江衢州324000 [3]天津大学化工学院,化学工程联合国家重点实验室,天津300072

出　　处：《化工学报》2021年第2期1169-1180,共12页CIESC Journal

基　　金：国家自然科学基金项目(21875213,21574115);化学工程联合国家重点实验室课题(SKL-ChE-19T01);浙江大学衢州研究院科技计划项目(IZQ2019-KJ-018)。

摘　　要：磷酸铁锂作为锂离子电池正极材料应用广泛。目前在其电极制备中仍采用PVDF油系黏结剂体系,可用于该电极的水性黏结剂仍需进一步研究。通过反应型乳化剂共聚苯乙烯(St)与丙烯酸异辛酯(2-EHA)制备了不同结构的磷酸铁锂正极水系黏结剂PSEHA,探讨了黏结剂对电池性能的影响。PSEHA黏结剂不含不饱和双键,抗氧化性好,较低的溶胀率可以有效防止过度溶胀导致的结构破坏,而反应型乳化剂可以解决乳化剂残留问题。采用所得最优结构黏结剂制备的磷酸铁锂电极表现出优异的电化学稳定性,扣式电池1 C循环100圈后容量保留率仍有96%,而SBR仅有93.9%;软包全电池在1 C倍率下循环170圈后容量保留率仍有98.9%。该新型水性黏结剂对促进磷酸铁锂水性体系制备有重要意义。LiFePO4 is a widely used cathode material for lithium-ion batteries.Polyvinylidenefluoride(PVDF),as a traditional organic solvent soluble binder,is still used in the preparation of LiFePO4 cathode.The water-based binder which can be used in the preparation of LiFePO4 cathode still needs to be further studied.A novel waterbased binder PSEHA with different structures for LiFePO4 cathodes was prepared via copolymerizing polystyrene(St)and 2-ethylhexyl acrylate(2-EHA)with a reactive emulsifier to improve the performance of lithium-ion battery.The influence of binder structure on battery performance was studied.Without unsaturated double bonds,PSEHA binder has good oxidation resistance.Its low swelling ratio can effectively prevent structural damage caused by excessive swelling,and the use of reactive emulsifiers can solve the residue of emulsifier.The LiFePO4 cathode prepared with the optimal binder showed excellent electrochemical stability.After 100 cycles,the LiFePO4 cathode in coin cells maintained stable cycling performance with retention of 96%at the rate of 1 C,while the SBR was only 93.9%.The capacity retention rate of the soft-packed full battery after 170 cycles at 1 C rate is still 98.9%.This new type of water-based binder is of great significance to promote the preparation of LiFePO4 cathode in waterbased systems.

关 键 词：电化学 电极黏结剂 乳液 聚合物 丙烯酸酯黏结剂 反应型乳化剂 磷酸铁锂正极 锂离子电池 

分 类 号：TQ028.8[化学工程]