Electrospun membranes based on PVdF-PEO blends for lithium batteries

Solid polymer electrolytes in lithium batteries have the dual function of electrolyte and separator to hinder lithium dendrite growth that causes hazardous short circuits during repeated charge/discharge cycles. Given the good compatibility between polyvinylidene difluoride (PVdF) and polyethylene oxide (PEO) and with the aim to merge the properties of these two polymers, we prepared and characterized PVdF/PEO membranes that act as separators and as hybrid gel polymer electrolytes when soaked in the liquid electrolyte with lithium salt. The membranes based on the polymer blends were prepared by electrospinning, a technique that yields micro-nanofibrous membranes with high porosity and, hence, huge values of electrolyte uptake. PEO 100,000 and PEO 1,000,000 were used to prepare two blends with PVdF:PEO 90:10 w/w composition. The electrochemical performance of the membranes, which were soaked in 1M LiPF6 - ethylene carbonate:dimethyl carbonate (1:1 w/w), was evaluated in Li//LiFePO4 and graphite//LiFePO4 cells and discussed.