High rate capabilities of Li4Ti5−xVxO12 (0 ≤ x ≤ 0.3) anode materials prepared by a sol–gel method for use in power lithium ion batteries

Abstract

Spinel-type vanadium-doped Li₄Ti_5−xV_xO₁₂ (0 ≤ x ≤ 0.3) samples (LTOVs) were synthesized via a sol–gel method. It was found that the LTOV samples consisted of nanoparticles 5–15 nm in diameter. The V doping did not result in any change of phase in the structure and barely affected the lattice parameters, although it did vary the ratio of the Ti³⁺ and Ti⁴⁺ oxidation states. The electrochemical analyses showed that the best discharge capacities were obtained from the Li₄Ti_5−xV_xO₁₂ (x = 0.06) electrode (LTOV06 electrode) in the voltage range 1–2.5 V at 0.2, 0.5, 1, 2 and 5 C with 208, 198, 189, 179 and 157 mA h g⁻¹, respectively. At 1 C the discharge capacity remained at 186 mA h g⁻¹ after 50 cycles, maintaining a good cycle performance. In the voltage range 0–2.5 V at 5 C, the initial discharge capacity of the LTOV06 electrode was 243 mA h g⁻¹ and 89% was retained after 250 cycles. These results indicate that LTOV06 is a promising high rate anode material for lithium ion batteries.