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

Abstract In this paper, Fe 3 O 4 nanoparticles (Fe 3 O 4 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 Fe 3 O 4 /C hollow nanospheres (HNSs) by thermal decomposition. After vulcanization and phosphating, Fe 3 O 4 /C HNSs are transformed into Fe 7 S 8 /C HNSs and Fe(PO 3 ) 2 /Fe 2 O 3 /C HNSs, respectively. Compared with Fe 3 O 4 /C HNSs and Fe(PO 3 ) 2 /Fe 2 O 3 /C HNSs, Fe 7 S 8 /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 Fe 7 S 8 /C HNSs is 1006 mA h g −1 after 250 cycles. The rate performance and electrochemical properties of Fe 7 S 8 /C HNSs are significantly improved. Research shows that the capacitive behavior plays a major role in specific capacity contribution of Fe 7 S 8 /C HNSs electrode. The anchoring of Fe 7 S 8 NPs on the shell of HMCNs avoids the aggregation of Fe 7 S 8 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.