Highly Stable Oxygen Electrodes Enabled by Catalyst Redistribution through an In Situ Electrochemical Method

In this work, for the first time an in situ electrochemical pretreatment approach to fabricate a highly reversible oxygen electrode with redistributed ultrafine RuO2 catalysts on a carbon nanotube (CNT) matrix is reported. The optimally pretreated RuO2/CNT oxygen electrodes demonstrate an extremely stable cycling life, 800 times with non-Li metal anode, under a capacity-limited protocol of 800 mAh g(-1) in an ether-based electrolyte in an O-2 environment. The highly stable activity of ultrafine RuO2 catalysts in oxygen reduction and evolution processes originates from the synergetic effect of greatly reduced size of catalyst (<2 nm) and uniform redistribution of catalyst particles after the in situ electrochemical pretreatment process. The pretreatment method discovered in this work can not only significantly enhance the activity/efficiency of the catalysts used for air electrodes but can also be widely applied to other electro-catalysis systems.