Rational design of Au dotted Co₃O₄ nanosheets as an efficient bifunctional catalyst for Li–oxygen batteries

摘要

Two-dimensional Co₃O₄ nanosheets dotted with Au nanoparticles were synthesized on the carbon gas diffusion layer as a bifunctional catalyst for Li–O₂ batteries by thermal evaporation and low-temperature calcination. The two-dimensional Co₃O₄ nanosheets improved the catalytic activity and Au nanoparticles provided additional nucleation sites for the Li₂O₂ growth in the process of discharge, thus allowing the uniform formation of Li₂O₂. Moreover, the size and distribution of Au nanoparticles were tuned by evaporating Au in different thicknesses. The catalytic performance of the Co₃O₄–Au hybrid was improved due to the synergetic effects of both materials and the improvements were closely associated with the size and distribution of Au nanoparticles. When the rationally designed catalyst was used as a cathode catalyst in Li–oxygen batteries, it lowered the polarization effect during cycling and realized the stable cyclability for 70 cycles at a limited capacity of 1000 mA h g?1.