Hybrid thermal resistant electrospun polymer membrane as the separator of lithium ion batteries

A heat resistant, anti-thermal-shrinkage, hybrid, electrospun nano-fibrous polymer membrane separator was synthesized. Three polyacrylonitrile (PAN)-based hybrid membranes were prepared by electrospinning different concentrations of pyromellitic dianhydride (PMDA) and 4,4'-oxydianiline (ODA) followed by oven drying to remove the residual solvent and thermal pressing to achieve the optimal strength and porosity in the membranes. The electrospun hybrid membranes were assessed as separators in lithium-ion batteries (LIBs) in a coin cell. Compared to the commercially available Celgard and PAN separator, the Hybrid3 membrane showed the highest porosity (73.36%), excellent electrolyte uptake (558.63%), and extraordinary ionic conductivity (2.39 mScm(-1)). Scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis were applied to examine the electrospun nano-fibrous separator membranes. The Hybrid3 membrane separator exhibited good dimensional stability when exposed to a temperature of 250 degrees C for 1 h. Electrochemical measurements were applied to investigate the electrochemical performance of the commercial Celgard and hybrid electrospun nano-fibrous membranes. The Hybrid3 membrane exhibited better electrochemical stability towards the electrolyte than the commercial Celgard separator and other hybrid electrospun nano-fibrous membrane. The coin cell constructed by the Hybrid3 membrane separator exhibited high specific capacity (184 mAh.g(-1)) at 1C. Moreover, at 0.5C, the coin cell assembled using the Hybrid3 membrane showed good cyclability and capacity retention (95.57%), as well as better efficiency (99.8%). The Hybrid3 membrane is a capable separator to boost the cyclability and provide thermally safe LIBs.