Facile synthesis of core–shell porous Fe$_{{3}}$O$_{{4}}$@carbon microspheres with high lithium storage performance

Core–shell porous Fe3O4@C (CP-Fe3O4@C) microspheres were synthesized using an environmentally viable hydrothermal method. Carbonization can reduce Fe2O3 and provide a conductive coating simultaneously. CP-Fe3O4@C microspheres as an active material for Lithium-ion batteries demonstrate pseudocapacity for improved rate performance. With a distinct nanostructure and pseudocapacitive effect, the CP-Fe3O4@C microspheres show excellent electrochemical performance (${\sim }785~\mathrm{mAh}{\cdot }\mathrm{g}^{-1}$ at $0.3~\mathrm{A}{\cdot }\mathrm{g}^{-1}$ after 200 cycles). Capacity measurements of CP-Fe3O4@C microspheres suggest near 90% pseudocapacitance at relatively low scan rates ($5~\mathrm{mV}{\cdot }\mathrm{s}^{-1}$).