An oxygen-deficient strategy to boost lithium storage of metal-organic framework-derived ZnTiO3/TiO2/C composite anodes

Abstract

With the growing demand for better electrochemical properties of lithium-ion batteries (LIBs), the design and development of alternatives for commercial electrodes has become an emerging field in energy research arena. In this paper, we reported an effective strategy using a bimetallic zeolite imidazole framework ZIF-8 (Zn, Ti) as the sacrificial template for synthesis of the oxygen-deficient ZnTiO3/TiO2/C (ZTC) composite as an advanced anode material for LIBs. Benefitting from the nanostructure retained from the MOF precursor, the unique electronic property provided by the abundant oxygen vacancies, synergistic effect of the multiphase composition, the ZTC composite prepared by calcination at 700 °C (ZTC-700) delivers not only a remarkable reversible capacity of 357.6 mA h g−1 at a current density of 300 mA g−1 after 400 cycles, but also an outstanding rate performance with a reversible capacity of 155 mA h g−1 at an elevated current density of 500 mA g−1 for 1500 cycles. To further investigate the lithium storage mechanism of the composites, density functional theory (DFT) calculation is employed to identify enhanced electrochemical performance of ZTC composites compared with pure rutile TiO2 due to the boosted diffusion kinetics. This study provids insights for the morphology and micro structure control from atomic level by MOF-templated method and the utilization of different components for better synergy.