PNNL

Abstract

Lithium-oxygen (Li-O2) batteries have been regarded as one of the most promising next-generation battery technologies. However, these batteries have very limited cycle life due to the lack of stable electrodes and electrolyte. In this work, we report an in-situ electrochemical pretreatment approach to fabricate a highly reversible oxygen electrode with redistributed ultrafine RuO2 catalysts on carbon nanotube (CNT) matrix. The optimally pretreated RuO2/CNT oxygen electrodes demonstrate an extremely stable cycling life, 800 times under a capacity-limited protocol of 800 mAh g-1, in an ether-based electrolyte in an O2 environment. These pretreated electrodes can also be discharged and charged for more than 170 cycles even in ambient conditions (relative humidity: 74 %). The nano-level redistribution method discovered in this work can not only significantly boost the activity/efficiency of the catalysts used for air electrodes, but can also be widely applied to other electrocatalysis systems.