Yttrium-modified Li4Ti5O12 as an effective anode material for lithium ion batteries with outstanding long-term cyclability and rate capabilities

Yttrium-modified Li4Ti5O12 (YLTO) was fabricated by a coprecipitation method using tetrabutyl titanate, Y(NO3)(3)center dot 6H(2)O and LiOH center dot H2O as reactants, followed by simply sintering the dried mixture at 600 degrees C. The products and their lithiation-delithiation process were characterized by a combination of electrochemical measurements, X-ray diffraction, transmission electron microscopy and nitrogen adsorption. The YLTO exhibits excellent long-term cycling stability (over 1000 cycles) at a high current rate of 10 C and outstanding rate capabilities. Particularly, the YLTO demonstrates remarkable cyclability even if directly cycled at a rate of 10 C without low-rate activation and with no relaxation between charge and discharge. Even without utilizing carbon black as conductive material, the YLTO still shows prominent rate capabilities and long-term cyclic performance at a rate of 5 C. The excellent performance is ascribed to the increased lattice constant, improved electronic and ionic conductivities, refined grains with large surface area and uniform nanopores resulting from the Y-modification.