Porous Fe2O3/Fe3O4@Carbon octahedron arrayed on three-dimensional graphene foam for lithium-ion battery

A rapid and simple way to prepare porous Fe2O3/Fe3O4@carbon octahedron arrayed on three-dimensional graphene foam (Fe2O3/Fe3O4@C/G) nanocomposites was developed. Firstly, Fe-metal organic frameworks (MOFs)/graphene oxide (GO) precursor was fabricated by growing octahedral Fe-MOFs on the surface of GO and then the as-prepared Fe-MOFs/GO was rapidly transformed into porous Fe2O3/Fe3O4@C/G by combusting the mixture of precursors and triethylamine (TEA) in air. In the combustion process, GO was reduced and connected each other into N-doped G foam, and Fe-MOFs were transformed into porous Fe2O3/Fe3O4@C octahedron and arrayed on G foam. The porous structure, porous carbon and G foam relieved the volume expansion of Fe2O3/Fe3O4 nanoparticles, and enhanced electrical conductivity of nanocomposites. The as-prepared Fe2O3/Fe3O4@C/G showed a high discharge capacity (1210 mAh g−1, 200 cycles) and long cycle life (5 A g−1, 400 cycles) when was applied to lithium-ion batteries. This work to prepare Fe2O3/Fe3O4@C/G nanocomposites through the combustion of TEA and Fe-MOFs/GO could save energy, achieve rapid preparation and shorten the reaction time. It might provide an original way for fabrication of transition metal oxides@C derived from MOFs and a constructive view into the preparation of composite materials.