The free-standing N-CoO matrix towards optimizing dual-electrodes for high-performance Li-O2 batteries

Abstract

Lithium-oxygen batteries (LOBs) have been developed because of their high theoretical energy density. However, both the dendrite/passivation problem of the anode and the sluggish ORR/OER kinetics of the cathode impede the improvement of batteries. Herein, N-doped CoO nanoarrays grown on carbon cloth (N-CoO/CC) are developed as a free-standing matrix for both improved anode and cathode of LOBs. The superior lithiophilicity and unique three-dimensional structure of the lithium-infused N-CoO/CC composite anode (Li@N-CoO/CC) can regulate Li plating/stripping behavior and suppress lithium dendrite, achieving a cycle lifespan of more than 2500 h in a symmetrical Li metal battery (1 mA cm−2, 1 mAh cm−2). In addition, the Li@N-CoO/CC anode alleviates it from corrosion of water/oxygen to some extent in Li-O2 batteries due to the Li2CO3-riched SEI formed after cycling. Moreover, N-doped CoO nanoarrays can catalyze the formation/decomposition of amorphous Li2O2, featuring a decreased overpotential. Based on the optimized dual electrodes, the resultant Li-O2 battery can maintain 200 cycles at 0.1 mA cm−2 within 0.25 mAh cm−2.