Improving the electrochemical properties of Al, Zr Co-doped Li₄Ti₅O₁₂ as a lithium-ion battery anode material

Li₄Ti₅O₁₂ and Al³⁺, Zr⁴⁺ co-doped Li_(4-x/3)Al_xTi_(5-5x/3)Zr_xO₁₂ (x = 0.01, 0.05, 0.1, 0.15, 0.2) were synthesized at 950 °C via a solid state reaction by using rutile TiO₂, Li₂ CO₃, and Al₂O₃ as precursors for the anode material of a lithium-ion battery. The average particle sizes of Li_(4-x/3)Al_xTi_(5-5x/3)Zr_xO₁₂ (x = 0, 0.01, 0.05, 0.1, 0.15, 0.2) range from 700 to 1200 nm. The particle sizes of pure Li₄Ti₅O₁₂ and Al³⁺, Zr⁴⁺ co-doped Li₄Ti₅O₁₂ were not obviously different, but did result in a shift in the (111) peak in X-ray diffraction. Li_(4-x/3)Al_xTi_(5-5x/3)Zr_xO₁₂ (x = 0.01) exhibits an excellent rate capability with a reversible capacity of 127.7 mAh/g at a 5 C-rate and even 113.1 mAh/g at a 10 C-rate. The capacity retention was improved remarkably compared to that for an undoped anode when discharged at a high C- rate.