锂离子电池塑料-金属复合集流体的特性及制备研究进展

Characteristics and preparation of metallized plastic current collectors for lithium-ion batteries

塑料-金属聚合物复合集流体(metallized plastic current collector,MPCC)通过减厚、减重可大幅提高电池的能量密度,且因聚合物自身绝缘、受热收缩、熔融等特性可提高电池的安全性,因此吸引了产业界研究者的诸多关注。了解聚合物基底和MPCC的特性及制备方法有利于高质量MPCC的研发,同时可促进高能量密度、高安全电池的发展,因此本文着重介绍了常用和亟待开发的聚合物的特性,阐明了目前市场生产的高质量PET、PP基复合集流体虽已应用于锂离子电池,但面临着各种挑战,例如PET的溶胀溶解反应,PP与金属层间的低黏结性等,并提出了相应的改进措施。此外,本文总结了聚合物表面沉积金属层的多种方法(磁控溅射、蒸镀、化学沉积和电镀等)的原理、优缺点和设备改良策略、注意事项,以期提高聚合物表面金属层的均匀性、一致性和导电率。最后,为提高MPCC在电池中的应用可行性,明确了MPCC未来研发的重点攻关问题,例如提高金属-聚合物界面黏结性,进一步提高电池安全性和导电率,并阐述了将来的发展趋势:功能化和精细化MPCC在电池中的应用。

Metallized plastic current collectors(MPCCs)have attracted considerable attention from industrial researchers as MPCCs can considerably increase the energy density of batteries by reducing the thickness and weight of devices.Furthermore,polymer properties,such as insulation,heat shrinkage,and melting considerably increase battery safety.Understanding the properties and preparation methods of polymer substrates and MPCCs is crucial for the development of high-quality MPCCs and the promotion of the development of high energy density and high-safety batteries.Therefore,this review focused on the properties of commonly used and potential polymers and clarified the advantages of high-quality polyethylene terephthalate(PET)-and polypropylene(PP)-based MPCCs applied to lithium-ion batteries as well as their fabrication and operational challenges,including the dissolution reaction of PET,low adhesion between PP,and metal layers.We have proposed measures to overcome these drawbacks.This paper summarizes the principles,advantages,disadvantages,and strategies(magnetron sputtering,evaporation,chemical deposition and electrochemical deposition,etc.)for depositing metal layers on polymer surfaces to improve the homogeneity,consistency,and electrical conductivity of the metal layers on polymer surfaces.Finally,to improve MPCC availability in batteries,the directions of developing MPCC,including improving the metal-polymer interfacial bonding,safety,and conductivity of batteries,as well as functionalizing and refining MPCC elaborated.