Nanoporous Anatase TiO₂ Mesocrystals: Additive-Free Synthesis, Remarkable Crystalline-Phase Stability, and Improved Lithium Insertion Behavior

Abstract

Unique spindle-shaped nanoporous anatase TiO(2) mesocrystals with a single-crystal-like structure and tunable sizes were successfully fabricated on a large scale through mesoscale assembly in the tetrabutyl titanate-acetic acid system without any additives under solvothermal conditions. A complex mesoscale assembly process involving slow release of soluble species from metastable solid precursors for the continuous formation of nascent anatase nanocrystals, oriented aggregation of tiny anatase nanocrystals, and entrapment of in situ produced butyl acetate as a porogen was put forward for the formation of the anatase mesocrystals. It was revealed that the acetic acid molecules played multiple key roles during the nonhydrolytic processing of the [001]-oriented, single-crystal-like anatase mesocrystals. The obtained nanoporous anatase mesocrystals exhibited remarkable crystalline-phase stability (i.e., the pure phase of anatase can be retained after being annealed at 900 °C) and improved performance as anode materials for lithium ion batteries, which could be largely attributed to the intrinsic single-crystal-like nature as well as high porosity of the nanoporous mesocrystals.

Self‐Templated Synthesis of Ultrathin Nanosheets Constructed TiO2 Hollow Spheres with High Electrochemical Properties

“…However, synthesis of this kind of hierarchical hollow structures is generally challenging due to the difference of stability between core and shell materials 24, 25. For example, TiO 2 is a kind of well‐known nanomaterials as photocatalysts,26, 27 and anode material of Li‐ion batteries,28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41 owing to its low cost, environmental benignity, physicochemical stability, and safety, but most of them are nanoparticles or primary nanoparticle‐constructed hollow spheres, very few researches involve the synthesis of 1D‐ or 2D‐constructed hollow spheres, through template methods 42, 43, 44…”

A nanocomposite superstructure of metal oxides with effective charge transfer interfaces

“…So far, a variety of mesocrystals of metal oxides (for example, TiO 2 , ZnO, Fe 2 O 3 and CuO) have been synthesized [6][7][8][9][10] . The method most commonly used to synthesize mesocrystal materials is based on hydrothermal/solvothermal treatments [11][12][13][14] , in which the solution should be maintained at a specific temperature and aged for a specific period of time. The resulting precipitates are then collected and washed to remove impurities, and, in some cases, the precipitates also require further annealing.…”

Recent Progress in Self‐Supported Metal Oxide Nanoarray Electrodes for Advanced Lithium‐Ion Batteries

“…Mesocrystals, which are crystallographically oriented nanoparticle superstructures with high crystallinity and high porosity, have been demonstrated to be promising electrode materials for LIBs 84, 85. We established a general method for facile kinetics‐controlled growth of aligned arrays of mesocrystalline SnO 2 nanorods on arbitrary substrates by adjusting supersaturation in a unique ternary solvent system 86.…”