An effective dual-channel strategy for preparation of polybenzimidazole separator for advanced-safety and high-performance lithium-ion batteries

Metal-organic framework (MOF) nanoparticles with an inherently ordered porous structure are a promising component for improving the safety of rechargeable batteries. However, a separator combining the polybenzimidazole (PBI) matrix and the MOF filler has not yet been developed to optimize lithium-ion batteries (LIBs). Here, an effective strategy has been designed to prepare the dual transport pathway separator containing poly (aryl ether benzimidazole) (OPBI) and the UiO-66 (zirconium-based MOF) filler using a phase separation method. The composite membranes show excellent properties, such as superior wettability, thermostability, flame resistance and interfacial compatibility, resulting from the interconnected porous network structure formed by the synergistic regulation of PBI porous structure and nano-MOF channels. Compared with the pristine OPBI separator, the composite separator (M40) containing 40% UiO-66 delivers a higher ionic conductivity, a significant improvement in LiFePO4/Li cell performance (151.6 mAh g(-1)), and an excellent rate capacity. Furthermore, the M40 exhibits the good uniformity of lithium electrodeposition and the effective inhibition of the lithium dendrite issues. The dual-channel strategy provides broader prospects for the application of the polybenzimidazole separator aided by the MOF crystals towards advanced-safety and high-performance LIBs.