The application and characteristics of hot-pressed, nanocomposite, polyethyleneoxide (PEO)-based electrolyte membranes in all solid-state rechargeable, Li/LiFePO4 polymer cells are presented and discussed. Both electrolyte separators and LiFePO4 composite cathodes were prepared by hot-pressing by a completely dry, solvent-free procedure. The thermal stability of both the PEO membranes and the composite cathodes was investigated. The cells were assembled by the direct lamination of the components, namely a lithium foil anode, the PEO-based electrolyte membrane and the composite LiFePO4 cathode tape. The Li/LiFePO4 polymer cells perform well in terms of specific capacity, charge/discharge efficiency and cycle life. At temperatures above 90°C, the cells are capable of delivering capacities exceeding 100mAh/g, even at moderately high rates. More than 400 cycles were obtained with a charge/discharge efficiency approaching 100%.