Self-assembled Fe3O4 nanoparticle-doped TiO2 nanorod superparticles with highly enhanced lithium storage properties

Abstract

Rational design of nanostructured anode materials is of importance for promoting the performance of lithium ion batteries (LIBs). Here the Fe₃O₄ nanoparticles (NPs) were controllably inserted into the matrix of TiO₂ nanorods (NRs) to obtain doped-superparticles (SPs) by a facile colloidal self-assembly route and subsequent calcination. To justify the effects of the doping, the lithium storage performances of the doped-SPs were evaluated as anode materials for LIBs. The results indicated that even a slight doping of Fe₃O₄ NPs can effectively enhance the properties of the anode materials compared with raw TiO₂ NR SPs. Additionally, the Fe₃O₄/(TiO₂)₇₀ SPs showed an optimal performance in term of specific capacity, rate capacity, and cycling stability, whose reversible capacity maintained around 550 mA h g⁻¹ at a current density of 1000 mA g⁻¹ after 400 cycles. The highly enhanced lithium storage of the Fe₃O₄ NP doped-TiO₂ NR SPs can substantially be attributed to the synergism of the doped-superstructure, in which the individual merits of the Fe₃O₄ NPs and TiO₂ NRs are fully played out. This work not only demonstrates the significant effects of Fe₃O₄ NP doping for TiO₂ NR SP anode materials in LIBs, but also opens an avenue for the self-assembly synthesis of doped-SPs with extended applications.