Mesocrystalline effect in a NiTiO3/TiO2 nanocomposite for enhanced capacity of lithium-ion battery anodes

A H2O2-modified layered titanate H1.07Ti1.73O4 (H2O2-HTO) is an excellent precursor for topochemical synthesis but its exfoliation reaction is unclear. Herein, we report the first study on the exfoliation reaction of H2O2-HTO and applications of H2O2-HTO and its nanosheets in the synthesis of NiTiO3/TiO2 nanocomposites as anode materials for lithium-ion batteries (LIBs). H2O2 in the interlayer space of H2O2-HTO can enhance ion-exchange capacity and exfoliation reaction kinetics. By reaction with Ni2+ solution, H2O2-HTO nanosheets were assembled into a HTO/Ni(OH)(2) sandwich layered structure which could be transformed into a polycrystalline NiTiO3/TiO2 nanocomposite with a sheetlike morphology and high NiTiO3 content by heat-treatment. A mesocrystalline NiTiO3/TiO2 nanocomposite with a plate-like morphology was obtained by heat-treatment of a Ni2+-exchanged H2O2-HTO. The electrochemical results suggested that these NiTiO3/TiO2 nanocomposites exhibit a synergistic effect of TiO2 and NiTiO3 for the enhanced reversible discharge-charge specific capacity as anode materials for LIBs. Furthermore, the NiTiO3 nanocrystals in the mesocrystalline NiTiO3/TiO2 nanocomposite show a much larger capacity than those in the polycrystalline one due to the fast passage for the Li+ migration in the mesocrystalline nanocomposite, namely the mesocrystalline effect.

Automated summary

This study investigates the exfoliation reaction of H2O2-modified layered titanate H1.07Ti1.73O4 (H2O2-HTO) and its applications in the synthesis of NiTiO3/TiO2 nanocomposites as anode materials for lithium-ion batteries (LIBs). It is found that H2O2 enhances the ion-exchange capacity and exfoliation reaction kinetics of H2O2-HTO. The nanosheets of H2O2-HTO can be assembled into sandwich layered structures and transformed into polycrystalline or mesocrystalline NiTiO3/TiO2 nanocomposites with different morphologies and properties. The NiTiO3 nanocrystals in the mesocrystalline nanocomposite show a much larger capacity due to the mesocrystalline effect.