Bio-Templating of Micro/Nanostructured Fe3O4/Carbon Composite for High-Performance Lithium-Ion Batteries

To meet the increasing demands on clean and efficient energy storage systems, rechargeable lithium-ion batteries (LIBs) are the most promising candidate for energy storage devices. They have attracted tremendous attention in both scientific and industrial fields. Intensive efforts have been devoted to exploring new electrode materials and to design novel nanostructures for LIBs. Among the available electrode materials, magnetite (Fe₃O₄) is regarded as an appealing material for LIBs due to its high theoretical storage capacity, natural abundance, as well as environmental friendiness. Herein, a green and facile strategy based on the in-vitro biomineralization of unicellular chlorella is reported to synthesize the micro/nanostructured porous Fe₃O₄/carbon composite for the use as anode material in high-performance lithium-ion batteries. The as-synthesized hierarchical Fe₃O₄/carbon composite exhibits a large reversible specific capacity (~660 mA h g^-1at 100 mA g^-1), excellent cyclic stability (~100% during the first 50 cycles), superior rate capacity and high Coulombic efficiency. It is found that the enhanced electrochemical performance is probably attributed to (i) the unique micro/nanostructure of Fe₃O₄/carbon composite having high specific surface area in comparison with other kinds of electrode materials, and (ii) the hierarchically distributed pore sizes via biomineralization of chlorella unicellular. This fabrication process is simple and low-cost, and introduces a new methodology to design and synthesize electrode materials for lithium-ion batteries.