基于h-BN/Al_(2)O_(3)共混涂层改性聚酰亚胺复合隔膜的制备与性能

Preparation and properties of polyimide composite separator modified by h-BN/Al_(2)O_(3) blended coating

通过非溶剂诱导相转化法制备高孔隙率的聚酰亚胺(PI)隔膜,并以六方氮化硼(h-BN)与纳米氧化铝(Al_(2)O_(3))为共混涂层对PI隔膜进行涂覆改性。通过调控h-BN与Al_(2)O_(3)质量比得到不同涂层效果的PI复合隔膜,并对其化学结构及微观形貌进行表征,同时探究隔膜的综合电化学性能以及隔膜对锂枝晶的抑制效果。结果表明,PI复合隔膜在h-BN与Al_(2)O_(3)的质量比为8∶2时,综合电化学性能最优,离子电导率与锂离子迁移数分别达0.871 mS/cm和0.54,在5 C高倍率下的放电比容量为118.9 mA·h/g,经过1 C电流密度下300圈循环后的容量保留率为80.2%,且能有效抑制锂枝晶的生长,保证电池长时间循环工作的稳定性。

Polyimide(PI)separator with high porosity was prepared by non-solvent induced phase transformation method,and the PI separator was modified by using hexagonal boron nitride(h-BN)and nano-alumina(Al_(2)O_(3))as blend coating.By adjusting the blending mass ratio of h-BN and Al_(2)O_(3),the PI composite separator with different coating effects was obtained.The chemical structure and micromorphology of the separator were characterized,and the comprehensive electrochemical performance of the separator and the inhibition effect on lithium dendrites were explored.The results show that when the mass ratio of h-BN and Al_(2)O_(3) is 8∶2,the PI composite separator shows the best comprehensive electrochemical performance.The ionic conductivity and lithium ions transfer number reached 0.871 mS/cm and 0.54,respectively.The discharge specific capacity was 118.9 mA·h/g at 5 C,and the capacity retention rate was 80.2%after 300 cycles at 1 C current density.The composite separator can effectively inhibit the growth of lithium dendrites and ensure the stability of the battery for a long-time cycle.