Rosa roxburghii-like hierarchical hollow sandwich-structure C@Fe2O3@C microspheres as second nanomaterialsfor superior lithium storage

Abstract

Fe2O3, as a promising advanced anode for the next generation lithium ion batteries, behaves high theoretical capacity and rich electrochemical properties. However, the poor cycle performances and low conductivity impede its extensive applications in lithium ion batteries. Herein, the von Mises stress distribution on solid spheres and hollow spheres were simulated by finite element method which confirmed the vital role of porous hollow spheres on strain-relaxation behavior as electrode materials. We also have developed a template method for the first preparation of rosa roxburghii-like hierarchical hollow sandwiched C@Fe2O3@C microspheres as second nanomaterials for superior lithium storage. As an advanced anode for lithium ion batteries, the porous C@Fe2O3@C microspheres exhibit reversible gravimetric capacity (1167 mAh g−1 after 100 cycles at 0.2 C), high rate performance (762 mAh g−1 after 1000 cycles at 1 C) and cycling stability without obvious capacity fading. The excellent performance is ascribed to the hierarchical hollow structure which can better withstand the stress produced in the process of ion embedding/stripping and alleviate the volume change of materials. On the other hand, the double carbon layer can effectively inhibit the self-aggregation effect of nano-scale Fe2O3 and provide a three-dimensional electronic network.