Dispersive Fe3O4 encapsulated in porous carbon for high capacity and long life anode of lithium-ion batteries

Abstract

With merits of large theoretical capacity and environmental benignity, Fe3O4-based materials are extensively researched as anodes in lithium-ion batteries (LIBs). However, they are faced with problems of low practical capacities and poor cycling durability. Herein, to achieve improved electrochemical kinetics and cyclic stability, the Fe3O4 is modulated to be dispersive nanoparticles and further encapsulated in a porous matrix by a well-designed strategy. Thanks to thus well-designed composite architecture, the as-prepared Fe3O4-based composite (Fe3O4@C) is given the improved electrochemical kinetics and structural stability, as demonstrated by the material and electrochemical characterizations. In addition to the synergistic effects of nanostructure and carbon coating that are commonly reported in Fe3O4/C composites, in our Fe3O4@C the unique space between dispersive Fe3O4 nanoparticles and the pores in carbon coating can improve electrolyte accessibility on the surface of the active material, enable rapid charges and ions transport and mitigate the change in volume, therefore achieving improved kinetics and superior structural stability. Consequently, the Fe3O4@C shows outstanding electrochemical properties, exhibiting high capacity of 864 mAh g−1 at 200 mA g−1 after 600 cycles as well as 514 mAh g−1 at 1000 mA g−1 after 600 cycles.