ZnFe2O4 nanoparticles embedded dispersedly inside 3D porous carbon framework as advanced anode materials of Li-ion batteries

Developing high-capacity anode materials is one of the crucial measures to effectively increase the energy density of Li-ion batteries. As a promising anode material, ZnFe2O4 has been widely concerned because of its high specific capacity and low cost. However, the inherent poor conductivity and dramatic volume changes during cycling restrict its further commercial development. In this paper, ZnFe2O4/C composites have been successfully designed by utilizing the self-swelling effect of gelatin to embed ZnFe2O4 nanoparticles inside 3D porous carbon dispersedly. At 200 mA g–1, ZnFe2O4/C obtained at 450 °C exhibits a high initial discharge specific capacity of 1367.1 mAh g–1. The excellent electrochemical performances are derived from the synergistic effect of ZnFe2O4 active nanoparticles and 3D porous carbon framework. Nano-sized particles can shorten the transport length of ions and electrons inside the active material. The presence of 3D porous carbon can realize high-speed charge transmission, facilitate the electrolyte infiltration, protect active particles, and buffer the structural destruction caused by volume change of metal oxide upon cycling. In addition, ZnFe2O4/C composites also show promising potential as anode materials of Na-ion batteries. This work provides a bright direction for the preparation of advanced anode materials for secondary rechargeable batteries.