The electrochemical performance of 20 mA h lithium-ion gel polymer cells, containing a macromonomer-based gel polymer electrolyte, was investigated in terms of cell capacity, high-rate capability, and accelerated aging characteristics at 50 degreesC. A 2-M LiBF4 in EC/GBL (3/7 by vol.) electrolyte was used in the fabrication of the pouch cells. The higher concentration of lithium salt increases the carrier ions in the gel polymer electrolyte and contributes to an increased discharge capacity at high Currents. The area specific impedance (ASI) of the cell, measured by the FreedomCAR hybrid pulse power characterization (HPPC) test method, was ca. 50 Omega cm(2) on an 18-s discharge pulse at 60% state-of-charge (SOC). This value is somewhat higher than that required for some high-power applications. (C) 2004 Elsevier B.V. All rights reserved.