High-Performance Lithium-Ion Storage of FeTiO3 with Morphology Adjustment and Niobium Doping

Abstract

Ferrous titanate (FeTiO3) has a high theoretical capacity and physical and chemical properties stability, so it is a potential lithium anode material. In this study, FeTiO3 nanopowder and nanosheets were prepared by the sol–gel method and the hydrothermal method. In addition, niobium-ion doping was carried out, the radius of Nb close to Ti so the Nb can easily enter into the FeTiO3 lattice. Nb can provide more free electrons to improve the electrochemical performance. Then, the effects of the morphology and niobium doping on the microstructure and electrochemical properties of FeTiO3 were systematically studied. The results show that FeTiO3 nanosheets have a better lithium storage performance than nanopowders because of its high specific surface area. A certain amount of niobium doping can improve the electrochemical performance of FeTiO3. Finally, a 1 mol% niobium-doping FeTiO3 nanosheets (1Nb-FTO-S) electrode provided a higher specific capacity of 782.1 mAh g−1 at 50 mA g−1. After 200 cycles, the specific capacity of the 1Nb-FTO-S electrode remained at 509.6 mAh g−1. It is revealed that an increased specific surface area and ion doping are effective means to change the performance of lithium, and the proposed method looks promising for the design of other inorganic oxide electrode materials.

Structural evolution and lithium-storage mechanism of the FeTiO3@Fe2TiO5 endogenous heterojunction

“…3(h) indicates that hetero-FTO exhibits a cycling performance that is superior to that of the majority of previously reported Fe–Ti–O-based electrode materials. 11,15,16,34,35,43,44 Furthermore, at a current density of 1 A g −1 (Fig. 3(g)), hetero-FTO exhibits a capacity of 261.3 mA h g −1 after 400 cycles, significantly surpassing that of FTO (97.3 mA h g −1 ).…”

“…For example, Nb doping in FeTiO 3 nanosheets introduces impurity energy levels, because of which more charge carriers participate in the conduction process and thus improve the electrochemical performance. 15 FeTiO 3 thin films deposited on N-doped carbon nanofiber substrates promote the formation of a conductive network. 10 FeTiO 3 /Fe/C composites can be prepared by combining iron and carbon to increase the electronic conductivity of FeTiO 3 , thereby improving the capacity of FeTiO 3 during cycling.…”