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

Abstract

A H₂O₂-modified layered titanate H_1.07Ti_1.73O₄ (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.