Improving Capacity and Thermal Degradation Characteristics of Li/(CF{sub}x){sub}n Cells using Anion Binding Agent in the Electrolyte

摘要

At Sandia National Laboratories, in an internally funded project, we are focusing on improving delivered capacity and more importantly thermal degradation characteristics of Li/(CF{sub}x){sub}n cells. We prepared (CF{sub}x){sub}n electrodes with two different thicknesses and tested them in coin cells in conventional organic electrolytes and in Sandia developed electrolyte containing anion-binding-agent (ABA) and LiF as Li salt. Both the delivered capacity and the thermal characteristics of the thicker electrodes (15 mils thick) that have Teflon as binder are better in ABA containing electrolyte. For example, 2016 coin cells containing ABA and LiF (despite low conductivity) showed ～10% higher capacity than those containing the highly conductive electrolyte (HCE). Similar trend was observed for cells aged 4 days at 80°C and tested at 25°C. However, with thinner electrodes (1.5-2 mil thick) that have PVDF as binder the delivered capacity was similar in the different electrolytes but the thermal behavior is better in ABA containing electrolyte. The room temperature conductivity of the ABA electrolyte is ～2.6mS/cm and that for the HCE is ～10mS/cm - around 4 times higher conductivity. Electrical and electrochemical data of the cells will be described in this paper.