Heterogeneous Interface\nDesign with Oxygen Vacancy-Rich\nAssistance High-Capacity Titanium-Based Oxide Anode Materials for\nSodium-Ion Batteries

Researchers are paying more attention to sodium-ion batteries\n(SIBs)\nbecause of their abundant supply of sodium resources and affordable\nprice. TiO<sub>2</sub> offers excellent safety and a long lifespan\nas an anode material for SIBs. However, the process kinetics is slow\ndue to its limited Na<sup>+</sup> storage efficiency, weak conductivity,\nand irreversible Na<sup>+</sup> capture. In order to address these\nissues, this review uses a mix of the template approach and the double-hydrolysis\nmethod to manage the structure and diffusion of TiO<sub>2</sub>-based\nanode materials by synthesizing FeTiO<sub>3</sub>/TiO<sub>2</sub> heterostructured\ndouble-shell microspheres (FTO). Through the built-in electric field\neffect caused by their heterostructures, FTO materials improve reaction\nkinetics, boost electronic conductivity, and lower the diffusion energy\nbarrier of Na<sup>+</sup>. Their distinctive double-shell structure\ncan increase electrolyte infiltration, shorten the diffusion distance\nbetween ions and electrons, and accommodate volume expansion during\ncycling. Furthermore, the irreversible capture of Na<sup>+</sup> and\nthe unfavorable interactions between the surface active site and electrolyte\ncan be successfully inhibited by FTO heterostructures. FTO has an\nexceptionally high capacity (reaching 362.7 mA h g<sup>–1</sup> after 60 cycles at 20 mA g<sup>–1</sup>) and excellent cycle\nstability (with a decay rate of 0.0061% after 1000 cycles at 2 A g<sup>–1</sup>). The strategy of constructing heterogeneous interfaces\nassists with high-performance SIB anode design.