Characterization of lithium zinc titanate doped with metal ions as anode materials for lithium ion batteries

Abstract

With the aim of improving the ionic and electronic conductivities of Li₂ZnTi₃O₈ for high performance lithium ion battery applications, Li₂Zn_0.9M_0.1Ti₃O₈ (M = Li⁺, Cu²⁺, Al³⁺, Ti⁴⁺, Nb⁵⁺, Mo⁶⁺) compounds are successfully fabricated using facile high temperature calcination at 800 °C. Physical characterization and lithium ion reversible storage demonstrate that Zn-site substitution by multivalent metal ions is beneficial for improving the migration rate of ions and electrons of Li₂ZnTi₃O₈. X-ray diffraction analysis and scanning electron microscopy reveal that the crystal structure and microscopic morphology of bare Li₂ZnTi₃O₈ do not change by introducing a small amount of foreign metal ions. As a result, Li₂Zn_0.9Nb_0.1Ti₃O₈ retains a reversible capacity as high as 198 mA h g^-1 at the end of the 500th cycle among all samples. Even when cycled at high temperatures, Li₂Zn_0.9Nb_0.1Ti₃O₈ still maintains excellent reversible discharge capacities of 210 mA h g^-1 and 196 mA h g^-1 at 1000 mA g^-1 for the 100th cycle at 50 °C and 60 °C, respectively. All the conclusions indicate that Li₂Zn_0.9Nb_0.1Ti₃O₈ is a high-performance anode material for large-scale energy storage devices.