Poly(vinylidene fluoride)-based, co-polymer separator electrolyte membranes for lithium-ion battery systems

Tests performed on Li/LiFePO4 and Li/Sn-C cells have revealed very good cycling performance even at high current rates and 100% of DOD, approaching the results achieved in liquid electrolytes. A capacity fading lower than 0.002% per cycle was observed. Particularly, the Li/LiFePO4 cathode cells have exhibited excellent rate capability, being still able to deliver at 2C above 89% of the capacity discharged at 0.1C. These results, in conjunction with the about 100% coulombic efficiency, suggest very good electrolyte/electrode compatibility, which results from the high purity and stability of the electrolyte and electrode materials and the cell manufacturing.