不同无机添加剂预制SEI膜的性能研究

Study on the performance of SEI film precast with different inorganic additives

以PVDF-HFP为基质,在铜箔上预制SEI膜,实现金属锂负极安全、稳定的工作。将不同种类和比例的无机添加剂混入基质中,通过对预制SEI膜进行扫描电镜、热重、拉伸、离子电导率等测试,研究了添加剂对预制SEI膜形貌、组成、强度等性能的影响。此外,以涂覆不同添加剂预制SEI膜的铜箔为正极,金属锂片为负极,制备扣式电池,研究了添加剂对预制SEI膜循环性能的影响。结果显示,添加纳米碳化硅晶须时,循环性能最优,较无添加时提升24.7%。添加不同类型的无机添加剂后,PVDF-HFP基质的晶粒尺寸、联结强度和孔结构等发生变化,从而影响基质的强度和离子电导率,基质的热稳定性也有不同程度的降低。

By using PVDF-HFP as the matrix,the SEI films were precast on copper foil to realize the safe and stable operation of lithium metal anode in this paper.The inorganic additives with different types and proportion were mixed into the matrix,and the effects of additives on the morphology,composition,strength and other properties of the precast SEI films were studied by scanning electron microscopy,thermogravimetric analysis,tensile and ionic conductivity tests.In addition,the copper foil coated with precast SEI film with different additives was used as the cathode,and the metal lithium sheet was used as the anode to prepare the coin cell.The influences of additives on the cycle performance of the precast SEI film were studied.The results showed that when the nano-silicon carbide whiskers were added,the cycle performance was the best,which is 24.7%higher than when no addition.After adding different types of inorganic additives,the grain size,connection strength and pore structure of the PVDF-HFP matrix changed,thus affecting the strength and ionic conductivity of the matrix,and reducing the thermal stability to varying degrees.