Coating with SiO2 alleviates the capacity decay of FeTiO3 for lithium storage

As a conversion-type anode material for lithium-ion batteries (LIBs), FeTiO 3 suffers from capacity fading due to the dissolution of Fe ions and the growth of solid electrolyte interphase (SEI) film. This hampers its practical application and further development in LIBs. To solve this issue, the microemulsion method (O/W) was used to encapsulate amorphous SiO 2 onto the surface of FeTiO 3 , constructing a FeTiO 3 @SiO 2 core-shell composite material. This strategy aims to alleviate the capacity loss caused by the rupture and detachment of active substances. The experimental results show that the FTO(FeTiO 3 ) electrode has a capacity of 300 mAh g −1 after 200 cycles at 100 mA g −1 , while the S 1 FTO(FeTiO 3 @SiO 2 ) electrode maintains a stable capacity of approximately 550 mAh g −1 . Furthermore, the capacity of the S 1 FTO (154.4 mAh g −1 after 500 cycles) still surpasses that of FTO (97.5 mAh g −1 after 500 cycles) at a current density of 1 A g −1 . Through ex situ XPS testing analysis of the variations under different current cycles, it is demonstrated that the SiO 2 coating has an inhibitory effect on the dissolution of Fe ions. This core-shell structure-design strategy is crucial for improving the lithium-storage performance of batteries, especially those containing conversion-type anode materials.