Sea-Sponge-like Structure of Nano-Fe3O4 on Skeleton-C with Long Cycle Life under High Rate for Li-Ion Batteries

To meet the demands of long cycle life under high rate for lithium-ion batteries, the advancement of anode materials with stable structural properties is necessarily demanded. Such promotion needs to design reasonable structure to facilitate the transportation of electron and lithium ions (Li⁺). Herein, a novel C/Fe₃O₄ sea-sponge-like structure was synthesized by ultrasonic spray pyrolysis following thermal decomposition process. On the basis of sea-sponge carbon (SSC) excellences in electronic conductivity and short Li⁺ diffusion pathway, nano-Fe₃O₄ anchored on stable SSC skeleton can deliver high electrochemical performance with long cycle life under high rate. During electrochemical cycling, well-dispersed nano-Fe₃O₄ in ∼6 nm not only averts excessive pulverization and is enveloped by solid electrolyte interphase film, but also increases Li⁺ diffusion efficiency. The much improved electrochemical properties showed a capacity of around 460 mAh g^-1 at a high rate of 1.5C with a retention rate of 93%, which is maintained without degradation up to 1000 cycles (1C = 1000 mA g^-1).