Evaluation of macromonomer-based gel polymer electrolyte for high-power applications

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 °C. 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 Ω cm2 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.