In the present paper, the physicochemical properties of a novel composite fibrous membrane, based on a mixture of poly(aryl ether sulfone) (PES) and poly(vinylidene fluoride) (PVDF), as separators for lithium-ion batteries are reported and discussed. Compared with the pure PVDF fibrous membrane, the introduction of PES can decrease the PVDF crystallinity while increasing the proportion of alpha-phase. Meanwhile, the initial thermal decomposition temperature is enhanced by 24 degrees C. Heat shrinkage tests and thermomechanical analyzers indicate the composite membrane has significantly improved thermal-dimensional stability. The shrinkage rate of the composite membrane after heat-treated at 180 degrees C for 2 hr is only 4.8%, which is far below the Celgard separator (82%) and the pure PVDF fibrous membrane (75%). The composite membrane with excellent wettability demonstrates a high ionic conductivity (1.69 x 10(-3) S cm(-1)) at room temperature as well as high electrolyte uptake (595%). The cells assembled with the composite membrane exhibit more stable cycle performance, capacity retention, and C-rate capability than that with polyolefin separator. These results suggest that PES/PVDF composite fibrous membrane is an effective separator for high-performance Lithium-ion batteries.

• Journal: Journal Of Applied Polymer Science
• Volume: 137
• Issue:
• Pages:
• ISSN: 0021-8995
• DOI:
• Year: 2020
• Number: 43
• Type: Journal Article