In Situ Derivatization for Boosted Lithium Storage Performance of Fe₇S₈/C Hollow Nanospheres

Abstract In this paper, Fe₃O₄ nanoparticles (Fe₃O₄ NPs) with an average diameter of 10 nm were grown in situ on the shell of hollow mesoporous carbon nanospheres (HMCNs) to form a new type of sesame balls‐like Fe₃O₄/C hollow nanospheres (HNSs) by thermal decomposition. After vulcanization and phosphating, Fe₃O₄/C HNSs are transformed into Fe₇S₈/C HNSs and Fe(PO₃)₂/Fe₂O₃/C HNSs, respectively. Compared with Fe₃O₄/C HNSs and Fe(PO₃)₂/Fe₂O₃/C HNSs, Fe₇S₈/C HNSs display good cycling stability as anode material for lithium ion batteries. When the current density is 1 A g⁻¹, the reversible specific capacity of Fe₇S₈/C HNSs is 1006 mA h g⁻¹ after 250 cycles. The rate performance and electrochemical properties of Fe₇S₈/C HNSs are significantly improved. Research shows that the capacitive behavior plays a major role in specific capacity contribution of Fe₇S₈/C HNSs electrode. The anchoring of Fe₇S₈ NPs on the shell of HMCNs avoids the aggregation of Fe₇S₈ NPs, promote the conductivity of composite and boost the delivery of electrons. This idea and expedient method of construction can be broadened to synthesize other hollow nanostructured material with preferable electrochemistry performance.