Highly Stable Cycling of Amorphous Li₂CO₃-Coated α-Fe₂O₃ 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 Li₂CO₃-coated nanocrystalline α-Fe₂O₃ 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 Li₂CO₃ layer is conformally coated on Fe₂O₃ nanocrystallines (≈10 nm in size) that form hierarchically aggregated particles 400–800 nm in size by ball milling α-Fe₂O₃ with LiH in CO₂. The prepared Li₂CO₃-coated nanocrystalline α-Fe₂O₃ exhibits highly stable long-term cyclability as it delivers a reversible capacity of 975 mAh g⁻¹ with 99% of retention after 400 cycles at 100 mA g⁻¹. At a high rate of 3000 mA g⁻¹, its reversible capacity still remains at 537 mAh g⁻¹, superior to the uncoated counterpart (311 mAh g⁻¹). Moreover, amorphous Li₂O and Li₂CO₃ coatings are also similarly produced on Fe₂O₃ and NiO nanocrystallines, respectively, representing the general applicability of this mechanochemical approach.