Comparative Study of the Electrochemical Performance of Different Separators in Aprotic Li–O2 Batteries

Nonaqueous lithium–oxygen (Li–O2) batteries have drawn the broad attention of researchers in recent years. A separator, as an indispensable component of a battery, significantly affects the electrolyte retention rate, ion conduction, and anode stability in a Li–O2 battery. However, a comprehensive comparison and analysis of the performance of commonly used separators in Li–O2 batteries are still lacking. In this study, systematic electrochemical performances of Li–O2 batteries with five kinds of commonly used separators Celgard 2400 (hereinafter referred to as Celgard), Whatman GF/A, GF/D, GF/F, and a laboratory-made gel polymer electrolyte (GPE) were investigated. Experimental results showed that batteries with GF/D and GD/F separators had far more stable cycling performances than those with GF/A, Celgard, and GPE, although the batteries with Celgard and GPE displayed similar discharge and charge capacity to the others. A slightly better cycling performance at the current rate of 200 mA g–1 was obtained with GF/F than with GF/D. Nevertheless, considering the much higher price of GF/F than that of GF/D, the latter could be the best candidate for validating the Li–O2 battery measurement. This study provides researchers with a valuable reference for choosing suitable separators for Li–O2 batteries from the perspectives of cost and performance, which would push forward the process of the practical application of Li–O2 batteries.