Highly Stable Cycling of Amorphous Li<sub>2sub>CO<sub>3sub>-Coated α-Fe<sub>2sub>O<sub>3sub> Nanocrystallines Prepared via a New Mechanochemical Strategy for Li-Ion Batteries
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- 作者：Yaxiong Yang ; Yongfeng Liu ; Kaichao Pu ; Xing Chen ; He Tian ; Mingxia Gao ; Min Zhu and Hongge Pan
- 刊名：Advanced Functional Materials
- 出版年：2017
- 出版时间：January 19, 2017
- 年：2017
- 卷：27
- 期：3
- 全文大小：5304K
- ISSN：1616-3028
文摘
In this study, an amorphous Li<sub>2sub>CO<sub>3sub>-coated nanocrystalline α-Fe<sub>2sub>O<sub>3sub> hierarchical structure is synthesized for the first time using a facile one-step mechanochemical process at room temperature, taking advantage of the concurrence of repeated fracture-cold welding of material's particles and a gas-solid redox reaction. The conformal coating and hierarchical structure significantly increase the cycling durability and rate capability. Typically, a 1–3 nm thick amorphous Li<sub>2sub>CO<sub>3sub> layer is conformally coated on Fe<sub>2sub>O<sub>3sub> nanocrystallines (≈10 nm in size) that form hierarchically aggregated particles 400–800 nm in size by ball milling α-Fe<sub>2sub>O<sub>3sub> with LiH in CO<sub>2sub>. The prepared Li<sub>2sub>CO<sub>3sub>-coated nanocrystalline α-Fe<sub>2sub>O<sub>3sub> exhibits highly stable long-term cyclability as it delivers a reversible capacity of 975 mAh g<sup>−1sup> with 99% of retention after 400 cycles at 100 mA g<sup>−1sup>. At a high rate of 3000 mA g<sup>−1sup>, its reversible capacity still remains at 537 mAh g<sup>−1sup>, superior to the uncoated counterpart (311 mAh g<sup>−1sup>). Moreover, amorphous Li<sub>2sub>O and Li<sub>2sub>CO<sub>3sub> coatings are also similarly produced on Fe<sub>2sub>O<sub>3sub> and NiO nanocrystallines, respectively, representing the general applicability of this mechanochemical approach.