Electrospinning Preparation Of Lithium-ion Battery Separator And The Influence Of Gd³⁺ Doping On The Magnetic Properties Of SmFeO₃

As the most commonly used electrical energy storage device for portable electronic devices and electric vehicles,lithium ion batteries have received more and more attention for their excellent performance.Battery separators are an important part of lithium-ion batteries,and their performance directly affects the storage capacity and safety performance of lithium batteries.Conventional polyolefin-based separators have low porosity and poor wettability to electrolytes,especially the problem of heat shrinkage,which greatly limits the development of lithium-ion batteries.Electrospun nanofibers have the advantages of small diameter,high specific surface area,high porosity,small pore size and uniformity.Therefore,the lithium ion battery separator prepared by electrospinning has high liquid absorption rate,liquid retention rate and lithium ion conductivity.Based on the above problems,the inorganic flexible SiO₂ battery separator was prepared by electrospinning technology,which has an"absolute"thermal safety guarantee.The porosity of the SiO₂ battery separator is 88.6%,which is more than twice that of the ordinary PP separator.At the same time,it exhibits better electrolyte wetting performance and electrochemical stability.Its high porosity makes the electrolyte absorption rate reach633%,and lithium ion.The conductivity reached 1.53 mS cm^-1.The cycle and rate performance of the lithium battery prepared using the SiO₂ separator was remarkably improved.On the basis of the SiO₂ separator,a PVDF-HFP fiber membrane prepared by an electrospinning technique is compounded in order to improve the mechanical strength of the separator and achieve a safe closed cell effect.Tensile testing showed that the mechanical strength of the composite membrane was more than doubled compared to the pure SiO₂ separator.The SEM showed that the composite separator exhibited a large-area closed cell phenomenon after heat treatment at 180°C.The composite separator maintains the advantages of high porosity and electrolyte absorption rate,and the battery cycle and rate performance prepared using the composite separator are significantly improved relative to the PP separator.In addition,we also studied the effect of Gd³⁺doping on the magnetic properties of SmFeO₃.The test results show that the doping of Gd³⁺significantly increases the magnetic susceptibility and saturation magnetization of SmFeO₃.