Improvement of PAN separator properties using PVA/malonic acid by electrospinning in lithium ion-batteries

The prominent objective of this study is to improve the thermal shrinkage and wettability of lithium-ion battery membrane separators based on Polyacrylonitrile (PAN) formed using an electrospinning technique. To achieve this goal, a PAN blended with highly hydrophilic Polyvinylalcohol (PVA) is formed, using malonic acid (MA) as a cross-linker. Due to the excellent hydrophilic properties of PVA and the network formation inside the separators (because of the MA crosslinker presence), the results show significant improvement in the separator properties. For this reason, at the optimum concentrations of 5 wt.% PVA and 5 wt.% MA (sample F4), an increase of wettability (contact angle from 85 degrees for pure PAN to 42 degrees for the F4 separator) is able to be seen. The electrolyte uptake was significantly increased, as for the F4 sample is increased to 1,150%, which is 2.67 times higher than the PAN with 430%. The improved separators showed higher porosity, better tensile strength, lower thermal shrinkage, and better electrochemical performance than the pure PAN separator. It showed an ion conductivity of 3.03 mS/cm, a wide electrochemical stability window of 5.2 V and an initial discharge capacity of 156.4 mAh/g.