Co/Zn‐based bimetallic MOF‐derived hierarchical porous Co/C composite as cathode material for high‐performance lithium‐air batteries

摘要

Summary Structural optimization and electrocatalyst utilization in air cathodes have been identified as two major factors affecting the overall performance of a lithium‐air battery. Herein, a cobalt@porous carbon composite, Co@C(700‐1000) was obtained by facile annealing of a Co/Zn‐bimetallic metal‐organic framework (MOF). In the Co/Zn‐MOF, cobalt cluster was used as a precursor of the catalyst and zinc cluster as a sacrificial template to generate meso‐ and macropores. The lithium‐air battery with the assembled Co@C(700‐1000) air cathode revealed a specific capacity as high as 4 mAh cm?2. Furthermore, the battery exhibited high cycling stability up to 67?cycles (limited capacity of 0.5 mAh cm?2). The high cell performance can be in relation to the catalytic activity of uniformly disseminated cobalt nanoparticles in the porous carbon matrix and the rapid diffusion and transport of Li+ and O2 owing to the optimized pore‐distribution characteristics. Using a bimetallic MOF‐derived material, this study sheds fresh light on the design of an air cathode for lithium‐air batteries.