Three-dimensional Fe2O3 nanocubes/nitrogen-doped graphene aerogels: nucleation mechanism and lithium storage...

We developed a solvothermal-induced self-assembly approach to construct three dimensional (3D) macroscopic Fe2O3 nanocubes/nitrogen-doped graphene (Fe2O3-NC/GN) aerogel as anode materials for lithium-ion batteries (LIBs). The Fe2O3 nanocubes with length of ~50 nm are homogeneously anchored on 3D GN frameworks and as spacers to separate the neighboring GN sheets. Based on intensively investigations on the early stages of formation process, it is discovered that a non-classical nanoparticle-mediated crystallization process and a subsequent classical ion-mediated growth dominate the nanocube formation. This is totally different from the commonly recognized classical atom-mediated crystallization and ripening mechanism. Benefitting from the unique structures and characteristics, the optimized Fe2O3-NC/GN aerogel exhibits excellent rate capability, outstanding long-term cyclic stability at high current densities, which are outperforming most of Fe2O3/GS hybrid electrodes. These results suggest us to in-depth understand the detailed crystallization process, and rational design and precisely control the morphologies of nanocrystals on graphene for high performance energy applications.