Poly(vinylidene fluoride)/SiO₂ composite membranes prepared by electrospinning and their excellent properties for nonwoven separators for lithium-ion batteries

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• 作者：Feng Zhang ; Xilan Ma ; Chuanbao Cao ; Jili Li ; Youqi Zhu
• 关键词：Poly(vinylidene fluoride) ; Silicon dioxide ; Nonwoven separator ; Electrospinning ; Lithium-ion battery
• 刊名：Journal of Power Sources
• 出版年：1 April, 2014
• 年：2014
• 卷：251
• 期：Complete
• 页码：423-431
• 全文大小：2657 K

文摘

PVdF/SiO₂ composite nonwoven membranes exhibiting high safety (thermal stability), high ionic conductivity and excellent electrochemical performances are firstly prepared by electrospinning poly(vinylidene fluoride) (PVdF) homopolymer and silicon dioxide (SiO₂) sol synchronously for the separators of lithium-ion batteries (LIBs). Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and hot oven tests show that the PVdF/SiO₂ composite nonwoven membranes are thermally stable at a high temperature of 400聽掳C while the commercial Celgard 2400聽PP membrane exhibits great shrinkage at 130聽掳C, indicating a superior thermal stability of PVdF/SiO₂ composite nonwoven membranes than that of Celgard membrane. Moreover, the composite membrane exhibits fairly high ionic conductivity (7.47聽脳聽10^鈭?聽S聽cm^鈭?) that significantly improves the performance of LIBs. The PVdF/SiO₂ composite membranes are also evaluated to have higher level of porosity (75鈭?5%) and electrolyte uptake (571鈭?46聽wt%), lower interfacial resistance compared to the Celgard separator. The lithium-ion cell (using LiFePO₄ cathode) assembled with the composite membrane exhibits more stable cycle performance, higher discharge capacity (159聽mAh聽g^鈭?) and excellent capacity retention which proves that they are promising candidates for separators of high performance rechargeable LIBs.