Rechargeability and rate capability of polymer electrolyte batteries at different temperatures
Abstract A highly conductive ambient temperature Li polymer electrolyte has been developed. The polymer electrolyte conductivity ranges from 0.5 mS/cm at -25°C to 2 mS/cm at 50°C, conductivities which are among the highest reported for polymer electrolytes. Flat lithium polymer electrolyte batteries have been made based on in situ radiation polymerization of the polymer electrolyte. The performance in terms of discharge capacity, rechargeability and charge retention during cycling at temperatures ranging from -25°C to +50°C have been characterized. Capacity utilization at room temperature above 90% of the theoretical capacity has been realized with current densities as high as 1 mA/cm2. At subroom temperature a reduction in the capacity utilization was observed down to 20% at -25°C. This reduction is due to diffusion limitations. The battery performance realized with the polymer electrolyte is particularly interesting as it appears to have overcome the inherent difficulties seen in all-solid-state batteries with respect to low electrolyte conductivities and rate capability.