Polyimide (PI) nanofiber membrane prepared by electrospinning technique exhibits poor mechanical strength for the slippage of fibers, which limits it applied into lithium ion battery (LIB). In this study, we are devoted to promoting the macro mechanical strength of PI nanofiber membrane by inhibiting the slippage among the fibers. Lithium polyacrylate (PAALi) is a kind of excellent binder, and it contributes to increasing the adhesion effect between the fibers. As a result, the PI nanofiber membrane treated by PAALi solution shows the mechanical strength of 16.1 MPa, higher than 5.0 MPa of pristine PI membrane. The introduction of this binder makes the originally loose and disordered PI nanofibers cross-link with each other and prevents from the slip between the fibers. Surprisingly, the PAALi binder has no effect on the thermal stability and electrochemical performance of PI nanofiber separator. Furthermore, these LiCoO₂/Li cells using the modified PI nanofiber separators exhibit better cycling stability and superior rate performance compared with the cells containing pristine PI separators. It demonstrates that the use of PAALi binder is a promising method to improve the mechanical strength of nanofiber membrane, which gets it applied in the high-power LIB.

通过电纺技术制备的聚酰亚胺（PI）纳米纤维膜对纤维的滑移表现出较差的机械强度，这限制了其在锂离子电池（LIB）中的应用。在这项研究中，我们致力于通过抑制纤维之间的滑动来提高PI纳米纤维膜的宏观机械强度。聚丙烯酸酯锂（PAALi）是一种优良的粘合剂，它有助于提高纤维之间的粘合效果。结果，用PAALi溶液处理的PI纳米纤维膜显示出16.1 MPa的机械强度，高于原始PI膜的5.0 MPa。这种粘合剂的引入使最初松散且无序的PI纳米纤维彼此交联，并防止了纤维之间的打滑。出奇，PAALi粘合剂对PI纳米纤维隔板的热稳定性和电化学性能没有影响。此外，这些LiCoO与包含原始PI隔板的电池相比，使用改良的PI纳米纤维隔板的₂ / Li电池具有更好的循环稳定性和优异的倍率性能。结果表明，PAALi粘结剂的使用是提高纳米纤维膜机械强度的一种有前途的方法，并使其应用于高功率LIB。