Preparation and performance of porous polyethersulfone (PES)/Al 2 O 3 separator for high-performance lithium-oxygen battery

The polymer separator is part of the gel polymer electrolyte (GPE) and plays a crucial role in battery. In this study, a novel PES-based separator for lithium-oxygen batteries was prepared using non-solvent-induced phase separation (NIPS) technique firstly and modified by doping Al 2 O 3 nanoparticles. It is proved that the properties of the PES/Al 2 O 3 separator are affected by the presence of Al 2 O 3 nanoparticles. The results show that the PES/Al 2 O 3 separator with Al 2 O 3 content of 2 wt% and 4 wt% has lower crystallinity, higher electrolyte uptake, and better mechanical properties and thermal stability than PES-based separator without Al 2 O 3 . The resulting PES/Al 2 O 3 separator containing 4 wt% Al 2 O 3 has higher ionic conductivity (0.49 mS cm −1 ) and lithium ions transference number (0.28). Consequently, the assembled batteries with the PES/Al 2 O 3 separator containing 4 wt% Al 2 O 3 exhibit excellent cycling performance (75 cycles, 1000 mAh g −1 at 0.05 mA cm −2 ). Therefore, PES/Al 2 O 3 separator has a significance meaning in the research of high-safety and long-cycle lithium-oxygen battery.