Synthesis of high performance Li4Ti5O12 microspheres and TiO2 nanowires from natural ilmenite

Abstract

The low cost production of Ti-containing nanomaterials from natural resources is an attractive method for producing materials suitable for the growing energy storage industry. In this work, natural ilmenite is transformed into either Li₄Ti₅O₁₂ microspheres or TiO₂ nanowires through a series of chemical and thermal processes by crossing metallurgy and material science. The produced well-crystallized Li₄Ti₅O₁₂ microspheres are composed of nanosized particles that show high cycle stability, coulombic efficiencies, and rate capability for C-rates as high as 20 C. The initial discharge capacities are 173.1, 168.5, 167.2, 163.4, 160.0, 155.4 and 142.7 mA h g⁻¹ at the 0.1, 0.5, 1, 2, 5, 10 and 20 C-rates, respectively. After 100 cycles, the as-prepared Li₄Ti₅O₁₂ retains 99.1%, 98.9%, 96.8% and 91.8% of its initial discharge capacities at the 2, 5, 10 and 20 C-rates, respectively. The synthesized echinus-like anatase TiO₂ nanowire aggregations also demonstrate excellent cycling performance, even at high current densities.