Fe/Fe3C decorated 3-D porous nitrogen-doped graphene as a cathode material for rechargeable Li-O2 batteries

Fe/Fe3C decorated 3-D porous N-doped graphene (F-PNG) is designed and synthesized via a one-step carbonization route. During the process, MIL-100(Fe), a kind of metal organic frameworks (MOFs) plays a structure-directing role. It is found that F-PNG with 3-D porous structure is constituted by N-doped graphene and extremely small Fe/Fe3C particles uniformly distribute on the surface of graphene. This rationally designed F-PNG possesses excellent oxygen reduction reaction and oxygen evolution reaction bifunctional electrocatalytic activity. While the material is explored as a cathode of Li-O-2 batteries, it exhibits excellent electrochemical performances, delivering a discharge voltage platform of similar to 2.91 V and a charge voltage platform of similar to 3.52 V at 0.1 mA cm(-2), showing a good cycle performance and having a discharge capacity of similar to 7150 mAh g(carbon+catalyst)(-1) at 0.1 mA cm(-2). The excellent performance of the F-PNG electrode is attributed to the good catalytic activity of uniformly distributed extremely small Fe/Fe3C particles and N-doped graphene, the high electronic conductivity, and the 3-D porous structure. These results indicate that F-PNG can be an excellent cathode material for Li-O-2 batteries, and MOFs-assisted synthesis method would be a promising new strategy for the synthesis of 3-D porous graphene materials. (C) 2016 Elsevier Ltd. All rights reserved.