A new solid polymer electrolyte, composed of a polymeric matrix of biodegradable polymer, poly-e-caprolactone (PCL) and 10% LiClO4 was used in a rechargeable lithium polymer battery. A LiNiCoO2 film prepared by the combination of sol-gel synthesis and a template concept was used as the cathode. Cyclic voltammetry, charge/discharge cycle and electrochemical impedance spectroscopy, were used to characterize the Li vertical bar PCL, 10% LiClO4 vertical bar LiNiCoO2 device. The specific charge/discharge capacity was determined to be 182 mAh g(-1) in the first cycles and 120 mAh g(-1) after 50 cycles. High lithium chemical diffusion coefficients values were obtained by electrochemical impedance spectroscopy. (c) 2005 Elsevier B.V. All rights reserved.