Lithium storage performance of {010}-faceted and [111]-faceted anatase TiO₂ nanocrystals

Abstract

As a popular anode material for lithium-ion batteries, anatase TiO₂ nanoparticles with exposed {001} facets usually exhibit exceptional lithium storage performance owing to more accessible sites and fast migration of lithium ions along the good crystalline channels. However, there are few researches on the lithium storage capability of TiO₂ nanocrystals with other high-energy facets owing to lack of effective synthesis method for controlling crystal facets. Herein, anatase TiO₂ nanocrystals with exposed {010}- and [111]-facets are successfully prepared by using the delaminated tetratitanate nanoribbons as precursors. The electrochemical properties of these TiO₂ nanocrystals with high-energy surfaces and the comparison with commercial TiO₂ nanoparticles (P25) are studied. It is found that the cycle and rate performance of TiO₂ nanocrystals is highly improved by reducing the particle size of nanocrystals. Moreover, TiO₂ nanocrystals with exposed {010}- and [111]-facets exhibit better lithium storage capacities in comparison with P25 without a specific facet though P25 has smaller particle size than these TiO₂ nanocrystals, indicating that the exposed facets of TiO₂ nanocrystals have an important impact on their lithium storage capacity. Therefore, the synthesis design of high-performance TiO₂ materials applied in the next-generation secondary batteries should both consider the particle size and the exposed facets of nanocrystals.

摘要

作为锂离子电池的负极材料,具有{001}晶面的锐钛矿型TiO₂ 纳米晶体通常展现出良好的储锂 性能,这是由于该晶面具有更多的接触位点,同时锂离子沿着该晶格方向的扩散速度较快。然而,由 于缺乏有效控制TiO₂ 晶面的合成方法,对具有其它高能晶面TiO₂ 晶体的储锂性能的研究较少。本文 以剥离的钛酸盐纳米带为前驱体,通过水热法合成了具有{010}和[111]晶面的锐钛矿型TiO₂ 纳米晶体。 通过对该TiO₂ 纳米晶体的电化学性能进行研究,并与商业用的TiO₂ 纳米颗粒(P25)的性能进行比较, 发现通过减小TiO₂ 纳米晶的粒径,可以大幅度提高TiO₂ 纳米晶体的循环和倍率性能。此外,尽管P25 具有更小的粒径,相比没有特定晶面的P25,具有{010}和[111]晶面的TiO₂ 纳米晶体仍展现出更好的 储锂能力。这表明TiO₂ 纳米晶体的暴露晶面对其储锂性能同样具有重要影响。因此,在设计合成具有 高性能的TiO₂ 电极材料时,要同时考虑纳米晶体的粒径和暴露晶面等因素。