Coupling solid and soluble catalysts toward stable Li anode for high-performance Li–O2 batteries

Abstract

Promoting the Li2O2 particles formation in the electrolyte by soluble catalysts could achieve high capacities for Li–O2 cell. However, side reactions between the soluble catalysts and lithium metal anode and more importantly, the deposition of the solid Li2O2 particle on which side (lithium anode or oxygen cathode) is inevitable for the solution phase discharge process in Li–O2 batteries, leading to the obvious capacity decay. Here we design and create a partial soluble metal nitroxides frameworks (MNOFs) to promote the “marriage” between the soluble and solid catalysts to overcome the most stubborn of these challenges. Taking advantage of the partial soluble property in the electrolyte, the prepared MNOFs can be simultaneously applied as the soluble and solid catalysts. MNOFs dissolving balance between electrolyte and cathode could construct a bridge between the electrolyte and cathode, which can not only suppress the corrosion reactions on Li anode, but also target discharge products deposition on the cathode. A 1Ah Li–O2 cell with a high areal specific capacity of 40 ​mA ​h ​cm-2 was demonstrated under a relatively low overpotential (~ 0.6 ​V). By ideally bridging the soluble and solid catalyst, the reversibility is significantly improved.