MnCo2 O4 /MoO2 Nanosheets Grown on Ni foam as Carbon- and Binder-Free Cathode for Lithium-Oxygen Batteries.

Abstract

Carbon is usually used as cathode material for Li-O2 batteries. However, the discharge product, such as Li2 O2 and LiO2 , could react with carbon to form an insulating lithium carbonate layer, resulting in cathode passivation and capacity fading. To solve this problem, the development of non-carbon cathodes is highly desirable. Herein, we successfully synthesized MnCo2 O4 (MCO) nanoparticles anchored on porous MoO2 nanosheets that are grown on Ni foam (current collector) (MCO/MoO2 @Ni), acting as a carbon- and binder-free cathode for Li-O2 batteries, in an attempt to improve the electrical conductivity, electrocatalytic activity, and durability. This MCO/MoO2 @Ni electrode delivers excellent cyclability (more than 400 cycles) and rate performance (voltage gap of 0.75 V at 5000 mA g-1 ). Notably, the battery with this electrode exhibits a high energy efficiency (higher than 85 %). The advanced electrochemical performance of MCO/MoO2 @Ni can be attributed to its high electrical conductivity, excellent stability, and outstanding electrocatalytic activity. This work offers a new strategy to fabricate high-performance Li-O2 batteries with non-carbon cathode materials.