TiO2 (B) 纳米颗粒的锂化热力学和动力学,Journal of the American Chemical Society

当前位置： X-MOL 学术 › J. Am. Chem. Soc. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

TiO2 (B) 纳米颗粒的锂化热力学和动力学
Journal of the American Chemical Society ( IF 14.4 ) Pub Date : 2017-09-12 , DOI: 10.1021/jacs.7b05228
Xiao Hua _{1,

2} , Zheng Liu _{3,

4} , Michael G. Fischer ₁ , Olaf Borkiewicz ₅ , Peter J. Chupas ₅ , Karena W. Chapman ₅ , Ullrich Steiner ₁ , Peter G. Bruce ₆ , Clare P. Grey ₂

Affiliation

TiO2（B）近年来引起了相当大的关注，因为它在所有研究的二氧化钛多晶型物中表现出最大的容量，当该材料为纳米结构时，可以实现高倍率的锂嵌入性能。然而，由于其锂化机制的复杂性和探索纳米结构材料中锂结构的实际挑战，对锂化热力学的明确理解尚未建立。因此，使用原位/操作数 X 射线对分布函数 (PDF) 和电化学技术的组合，对 TiO2 (B) 纳米粒子进行了全面的机械研究。放电开始于与锂嵌入纳米颗粒的亚表面平行的表面反应。Li 本体插入从单相反应开始，进入 A2 位点，该位点与 b 通道相邻。在 Li0.25TiO2 的组成中，Li 扩散路径从沿该开放通道的路径更改为沿 c 方向的路径可能会发生在 Li0.5TiO2 的组成处，直到达到 Li0.5TiO2，导致两步 A2 位点结合一步在动力学上与另一个不同。随后的 Li 插入涉及 C' 位点，位于通道内部的位置，并遵循快速两相反应形成 Li0.75TiO2。由于与进一步锂化相关的高扩散势垒，Li 插入 A1 位点（与 A2 位点相邻的通道相邻的另一个位置）在动力学上受到限制。

"点击查看英文标题和摘要"

Lithiation Thermodynamics and Kinetics of the TiO2 (B) Nanoparticles

TiO2 (B) has attracted considerable attention in recent years because it exhibits the largest capacity among all studied titania polymorphs, with high rate performance for Li intercalation being achieved when this material is nanostructured. However, due to the complex nature of its lithiation mechanism and practical challenges in probing Li structure in nanostructured materials, a definitive understanding of the lithiation thermodynamics has yet to be established. A comprehensive mechanistic investigation of the TiO2 (B) nanoparticles is therefore presented using a combination of in situ/operando X-ray pair distribution function (PDF) and electrochemical techniques. The discharge begins with surface reactions in parallel with Li insertion into the subsurface of the nanoparticles. The Li bulk insertion starts with a single-phase reaction into the A2 site, a position adjacent to the b-channel. A change of the Li diffusion pathway from that along this open channel to that along the c-direction is likely to occur at the composition of Li0.25TiO2 until Li0.5TiO2 is attained, leading to a two-step A2-site incorporation with one step kinetically distinct from the other. Subsequent Li insertion involves the C' site, a position situated inside the channel, and follows a rapid two-phase reaction to form Li0.75TiO2. Due to the high diffusion barrier associated with the further lithiation, Li insertion into the A1 site, another position adjacent to the channel neighboring the A2 sites, is kinetically restricted. This study not only explores the lithiation reaction thermodynamics and mechanisms of nanoparticulate TiO2 (B) but also serves as a strong reference for future studies of the bulk phase, and for future calculations to study the Li transport properties of TiO2 (B).

更新日期：2017-09-12

点击分享查看原文

点击收藏

公开下载

阅读更多本刊新发论文本刊介绍/投稿指南