Robust erythrocyte-like Fe2O3@carbon with yolk-shell structures as high-performance anode for lithium ion batteries

To address the issues of sluggish electronic transport and large volume variation of Fe2O3 anode nanomaterials caused by repeated Li+ insertion/ extraction, herein we engineer an erythrocyte-like Fe2O3 with thin mesoporous carbon into yolk-shell architectures, in which the erythrocyte-like Fe2O3 is well confined inside the thin mesoporous carbon. In this design, the erythrocyte-like Fe2O3 cores with high specific capacity together with the permeable thin carbon shells could not only greatly facilitate the fast diffusion for both ion and electron but also retain a thin and stable solid electrolyte interface (SEI) layer on its surface, resulting in excellent rate capability and cycling stability. Meanwhile, the hollow cavity between carbon shell and Fe2O3 core provides extra free space for Fe2O3 expansion, thus preserving the structural integrity. By virtue of their advantageous structural features, the elegant void-containing mesoporous carbon-encapsulated erythrocyte-like Fe2O3 electrodes exhibit superior performance including large capacity, high rate capability and long cycle stability. More importantly, when coupled with commercial LiCoO2 cathode, the assembled Li-ion full cell demonstrates a high reversible capacity of 615 mA h g(-1) after 100 cycles at 1C with capacity retention of 83.4% as well as outstanding rate capability (675 mA h g(-1) at 4C with capacity retention of 83% from 0.2C to 4C), demonstrating significant potential for future practical applications.