Ultrasmall Fe 3 O 4 Nanoparticle/MoS 2 Nanosheet Composites with Superior Performances for Lithium Ion Batteries

A novel composite consisting of graphene‐like MoS 2 nanosheets and ultrasmall Fe 3 O 4 nanoparticles (≈3.5 nm) is synthesized as an anode for lithium ion battery application. In such composite anode, MoS 2 nanosheets provide flexible substrates for the nanoparticle decoration, accommodating the volume changes of Fe 3 O 4 during cycling process; while Fe 3 O 4 nanoparticles primarily act as spacers to stabilize the composite structure, making the active surfaces of MoS 2 nanosheets accessible for electrolyte penetration during charge/discharge processes. Owing to the high reversible capacity provided by the MoS 2 nanosheets and the superior high rate performance offered by ultrasmall Fe 3 O 4 nanoparticles, superior cyclic and rate performances are achieved by Fe 3 O 4 /MoS 2 anode during the subsequent electrochemical tests, delivering 1033 and 224 mAh g −1 at current densities of 2000 and 10 000 mA g −1 , respectively.