Turning carbon black into hollow carbon nanospheres to encapsulate Fe2O3 as high-performance lithium-ion batteries anode

Fe2O3 are attractive anode materials for lithium-ion batteries because of their large theoretical capacity and low cost. However, due to their low conductivity, large volume variation and unstable solid electrolyte interface (SEI), their cycling stability is poor. Herein, we developed a simple and general strategy to address these issues. The well-designed yolk-shell Fe2O3@C nanospheres with the inner Fe2O3 nanoparticles are protected by highly graphitized and interconnected carbon shells prepared by oxidizing commercial acetylene black. The obtained yolk-shell Fe2O3@C nanospheres provide sufficient interior void to buffer the volumetric variation of the inner Fe2O3 nanoparticles during cycling. Furthermore, the highly-graphitized and perforated mesoporous carbon shells facilitate fast electron transfer and ions transportation during the charge/discharge process. Benefiting from these structural advantages, the yolk-shell Fe2O3@C nanospheres provide good cyclic stability which still retain 929 mAh g(-1) after 200 cycles at the current density of 0.1 A g(-1) and elevate Li+ diffusion coefficient from 3.867 x 10(-13) to 6.321 x 10(-11) m(2) s(-1). This work provides a new perspective to design the yolk-shell metal oxides@C framework for exploring the high-performance Li-ion batteries.