Physiochemical properties of nonaqueous amine-containing electrolytes

Abstract

Recent developments in Li-CO2 batteries have demonstrated the viability of using amines to electrochemically activate CO2 before reduction and yield kinetic benefits, but little research has been done to optimize this new system. This thesis investigates the reduction of amine-activated CO2 and the properties of nonaqueous amine-containing electrolytes. The equilibrium voltage of the discharge reaction was found to be greater than 3.1 V versus Li/Lie, which is significantly higher than the thermodynamic potential of direct CO2 reduction (2.8 V versus Li/Lie). The equilibrium voltage can be used in future research to determine cell overpotentials, which are key indicators of cell performance. The research also found that varying the electrolyte salt and the type of amine can greatly increase the ionic conductivity of the electrolyte. Specifically, solutions containing salts with larger cations and larger anions were generally found to have larger ionic conductivities. These findings indicate that there is room to improve on and optimize the recently demonstrated amine-promoted Li-CO2 battery through more research into electrolyte and amine properties.