摘要
为了充分利用纳米纤维膜的多孔特性,同时克服其低机械强度的缺陷,以聚丙烯腈(PAN)为主要原料,采用静电纺丝法在石墨电极表面制备PAN纳米纤维膜,形成隔膜-电极一体化结构单元(SAA),并对SAA的孔道结构、力学性能、电解液性能、热尺寸稳定性及电池性能进行系统研究。结果表明:SAA中PAN隔膜与石墨电极的粗糙表面结合紧密,PAN隔膜呈现出发达的孔道结构,电解液亲和性良好;在150℃热处理0.5 h,SAA表面隔膜的热收缩率小于2%,显著优于市售聚烯烃隔膜。基于良好的理化特性,SAA装配的钴酸锂全电池表现出优异的循环容量和倍率容量保持性,如在0.2 C下,经历200次循环后电池的放电容量保持率为98%,在32 C下电池的放电容量为0.5 C下的44.3%。因此,电极表面直接制备纳米纤维膜可形成完整的隔膜-电极一体化单元,在充分发挥纳米纤维膜优势的同时,可优化电极与隔膜的界面相容性、改善电池的充放电性能,并能够提高电池的装配效率。
In order to make full use of the porous structure and overcome the shortcoming of low mechanical strength of nanofiber-based separators,polyacrylonitrile(PAN)separator was prepared directly on the surface of graphite anode by the electrospinning method.And an integrated separator/anode assembly(SAA)was formed.The microstructure,mechanical strength,electrolyte wettability,thermal resistance and battery performance were systematically investigated.The results show that the nanofibers in PAN separator are tightly bonded to the rough surface of graphite anode,resulting in a well-integrated interface structure(tensile strength higher than 200 MPa).Compared with polyolefin separators,SAA exhibits better electrolyte affinity and higher ion conductivity(1.9 mS/cm).The above advantages endow the LiCoO 2/SAA full cell with better C-rate(capacity retention 44.3%at 32 C compared with that at 0.5 C)and cycling performances(capacity retention 98%after 200 cycles at 0.2 C)compared with those of LiCoO 2/polyolefin separator/graphite battery.Consequently,this work provides an advanced separator/anode assembly and the corresponding fabrication method,which may be a new strategy for improving the charge-discharge performance and assembly efficiency of lithium-ion batteries.
作者
肖伟
杨占旭
乔庆东
XIAO Wei;YANG Zhan-xu;QIAO Qing-dong(School of Petrochemical Engineering,Liaoning Petrochemical University,Fushun 113001,Liaoning,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2021年第9期60-68,共9页
Journal of Materials Engineering
基金
国家自然科学基金项目(21676282,21671092)。
关键词
锂离子电池
纳米纤维膜
一体化单元
界面相容性
力学性能
充放电性能
lithium-ion battery
nanofiber separator
integrated assembly
interface compatibility
mechanical property
charge-discharge performance