Advanced electrochemical properties of Ce-modified Li₂ZnTi₃O₈ anode material for lithium-ion batteries

A series of Li₂ZnTi_3-xCe_xO₈ (x = 0, 0.05, 0.1, 0.15) anode materials have been synthesized via a facile solid-state method. XRD shows that the dopant Ce ions cannot completely enter the Li₂ZnTi₃O₈ lattice and an impurity phase CeO₂ appears in the three doped materials. The Li₂ZnTi_3-xCe_xO₈ (x = 0.05) sample exhibits the best rate capability among all the as-prepared samples, indicating its appropriate amount of Ce ions modification. The initial discharge specific capacities delivered by Li₂ZnTi_3-xCe_xO₈ (x = 0.05) are 317.6, 227.8, 210.4, 197.3, 187.7 and 181.1 mAh g⁻¹ at 0.5, 2, 5, 10, 15 and 20C, respectively, and a reversible capacity of 132.7 mAh g⁻¹ can be retained after 500 cycles at 10C with a capacity retention of 68.9%. The doping of Ce⁴⁺ can increase the intrinsic Li⁺ diffusion coefficient and CeO₂ scattering on the surface of Li₂ZnTi₃O₈ is beneficial to improve the extrinsic electronic conductivity. The synergistic effect is probably responsible for the excellent electrochemical performance of Li₂ZnTi_3-xCe_xO₈ (x = 0.05).