All- solid Li/ LiFePO4 lithium polymer batteries with nonflammable poly (ethylene glycol) borate ester- based polymer electrolyte have been constructed and successfully operated at ambient and elevated temperatures. The cell exhibited about 90% of the theoretical capacity at 0.1 C rate at 60 degrees C. The AlPO4 addition to the polymer electrolyte improved the Li/ LiFePO4 polymer cell rate performance and allowed stable prolonged cycling even at 2 C rate at 60 degrees C. The ac impedance spectroscopy data showed the electrode/ electrolyte interface stabilization and lowering of cell impedance in the presence of AlPO4. (c) 2007 The Electrochemical Society.