Novel Li-ion polymer batteries using LiFePO4 as positive electrode

Abstract

983-988The aging and performance of natural graphite/PEO-based gel electrolyte/ LiFePO4 cells have been reported. The gel polymer electrolytes have been produced by electron-beam irradiation and then soaked in a liquid electrolyte. The natural graphite anode in gel electrolyte containing LiBF4 -EC/GBL exhibits high reversible capacity (345mAh/g) and high coulombic efficiency (91%). The LiFePO4 cathode in the same gel-polymer exhibits a reversible capacity of 150 mAh/g and 83% coulombic efficiency. Better performance has been obtained at high-rate discharge with 6% carbon additive in the cathode. However, the graphite anode performance suffers at high rate. The Li-ion gel polymer battery shows a capacity fade of 13% after 180 cycles and has poor performance at low temperature. Li/polymer/LiFePO4 has an excellent stable cycle life