退火对PE-UHMW湿法锂离子电池隔膜的影响  

Effect of annealing on PE-UHMW wet process lithium ion battery separators

作　　者：唐玲玲 权家友 茆汉军 赵诚[1,2,3] 王新威 TANG Lingling;QUAN Jiayou;MAO Hanjun;ZHAO Cheng;WANG Xinwei(Shanghai Research Institute of Chemical Industry,Shanghai 200062,China;Shanghai Key Laboratory of Catalysis Technology for Polyolefin,Shanghai 200062,China;State Key Laboratory of Polyolefin and Catalysis,Shanghai 200062,China)

机构地区：[1]上海化工研究院,上海200062 [2]上海市聚烯烃催化技术重点实验室,上海200062 [3]聚烯烃催化技术与高性能材料国家重点实验室,上海200062

出　　处：《工程塑料应用》2024年第11期71-78,共8页Engineering Plastics Application

基　　金：上海市国资委企业创新发展和能级提升项目(2022001)。

摘　　要：在锂离子电池的组成材料中,隔膜是关键的内层组件之一,隔膜是具有纳米级微孔结构的高分子功能材料,隔膜的性能对于电池的整体性能有着至关重要的影响,包括理化特性、力学性能、热性能及电化学性能等多个方面,其中,孔径大小与分布的均一性对电池性能有直接的影响,孔径分布越窄、越均匀,电池的电性能越优异。目前,商用锂电池隔膜以微孔聚烯烃膜为主,但聚烯烃膜的孔径大小难调控,限制了锂离子在锂电池正负极之间的传输效率。使用热致相分离法制备铸片,用退火的方式对铸片进行处理,并结合同步双轴拉伸工艺制备了孔径可调的超高分子量聚乙烯(PE-UHMW)锂离子电池隔膜,并通过差示扫描量热仪、X射线衍射仪、扫描电子显微镜、高温凝胶色谱仪、万能拉伸机和孔径分布仪等表征了PE-UHMW锂离子电池隔膜的基本性能,并对其退火机理进行了研究。结果表明,铸片退火后消除了挤出后一面接触冷辊一面接触空气形成的差异,经双向拉伸制备的隔膜结晶度和晶粒尺寸增大、力学性能更高、孔径增大、孔径分布更均匀。In the composition materials of lithium-ion batteries,the separator is one of the key inner components.The separator is a polymer functional material with a nanoscale microporous structure.The performance of the separator has a crucial impact on the overall performance of the battery,including physical and chemical properties,mechanical properties,thermal properties,and electrochemical properties.Among them,the uniformity of pore size and distribution has a direct impact on battery performance.The narrower and more uniform the pore size distribution,the better the electrical performance of the battery.At present,commercial lithium battery separators mainly use microporous polyolefin membranes,but the pore size of polyolefin membranes is difficult to control,which limits the transmission efficiency of lithium ions between the positive and negative electrodes of lithium batteries.A thermally induced phase separation method was used to prepare the cast piece,and the cast piece was annealed.Then,a ultra high molecular weight polyethylene(PE-UHMW)lithium-ion battery diaphragm with adjustable pore diameter was prepared by combining the synchronous biaxial stretching process.The basic performance of PE-UHMW lithium-ion battery diaphragm was characterized by differential scanning calorimetry,X-ray diffraction,scanning electron microscopy,high temperature gel chromatography,universal stretching machine and pore size distribution meter,and its annealing mechanism was studied.The results show that after annealing,the difference formed by one side contacting the cold roll and the other side contacting the air after extrusion was eliminated.The crystallinity and grain size of the diaphragm prepared by biaxial stretching increase,the mechanical properties are higher,the pore size increase,and the pore size distribution is more uniform.

关 键 词：超高分子量聚乙烯 热致相分离法 锂离子电池隔膜 退火 孔径可调 

分 类 号：TQ325.1[化学工程—合成树脂塑料工业]