复合锂离子电池隔膜的制备及其电化学性能

为获得性能较好的锂离子电池隔膜，首先制备了单层静电纺聚偏氟乙烯六氟丙烯（P（VDF-HFP））纳米纤维，然后利用静电喷雾技术将Al2O3和ZrO2颗粒分散液均匀喷洒在其表面，再接收一层静电纺P（VDF-HFP）纳米纤维，制备出具有3层结构的有机/无机复合锂离子电池隔膜。同时制备了单层静电纺P（VDF-HFP）纳米纤维膜作为对比膜。考察了复合膜和对比膜的表面形貌、透气性、吸液率和热稳定性等物理性能，以及室温离子电导率、电化学稳定性和电池的循环充放电性能等电化学性能。结果表明：该复合膜的Gurley值为0.117S/(100mL?cm²)，热收缩率为2.25%，吸液率为420%；室温下离子电导率为2.31mS/cm，电化学稳定窗口为5.4V，所制备电池首次放电比容量为138.6mA?h/g；在中间层添加纳米颗粒后，复合膜的透气性下降而其他指标均获得提升，综合性能优于相同条件下制备的单层静电纺隔膜

Preparation and electrochemical characterization of composite separator for lithium-ion battery

In order to obtain a better lithium-ion battery separator with good performance, the first layer of the membrane was prepared by electrospinning poly (vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP))polymer solutions, then alumina and zirconia microparticles were deposited on the surface by electrostatic electrostatic spraying, anda novel sandwiched composite membrane was formed followed by fabricate the other P(VDF-HFP)nanofibrous layerby electrospinning. The single-layerP(VDF-HFP) separator was prepared as acomparison by electrospun at the same time. The physical performance, including morphology, permeability, liquid electrolyte uptake and thermal stability, and electrochemical properties such as ionic conductivities of membranes at room temperature, electrochemical stability, and cycling performance of the two kinds of separators were investigated. The resultsdemonstrate that electrolyte uptake of the composite membrane is 420%, while the Gurley value andthermal shrinkageare0.117S/(100mL?cm²) , and20.25%, respectively. Good electrolyte uptake contributes to the ionic conductivity which is up to 2.31 mS/cm at room temperature, electrochemical stabilivity window is 5.4 V, and initialcycle charge and discharge capacity of the prepared battery is138.6 mA?h/g. Except for the small weakness in permeability, all the other properties of the composite membrane are improved. It’s found that the performance of the composite membrane is better than that of the single-layer electrospun P(VDF-HFP) separator under the same test conditions.