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

Abstract

Yttrium-modified Li₄Ti₅O₁₂ (YLTO) was fabricated by a coprecipitation method using tetrabutyl titanate, Y(NO₃)₃·6H₂O and LiOH·H₂O as reactants, followed by simply sintering the dried mixture at 600 °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.