Ammonium Fluoride Mediated Synthesis of Anhydrous Metal Fluoride–Mesoporous Carbon Nanocomposites for High-Performance Lithium Ion Battery Cathodes

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• 作者：Jinyoung Chun ; Changshin Jo ; Sunhye Sahgong ; Min Gyu Kim ; Eunho Lim ; Dong Hyeon Kim ; Jongkook Hwang ; Eunae Kang ; Keun Ah Ryu ; Yoon Seok Jung ; Youngsik Kim ; Jinwoo Lee
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：December 28, 2016
• 年：2016
• 卷：8
• 期：51
• 页码：35180-35190
• 全文大小：852K
• ISSN：1944-8252

文摘

Metal fluorides (MF_x) are one of the most attractive cathode candidates for Li ion batteries (LIBs) due to their high conversion potentials with large capacities. However, only a limited number of synthetic methods, generally involving highly toxic or inaccessible reagents, currently exist, which has made it difficult to produce well-designed nanostructures suitable for cathodes; consequently, harnessing their potential cathodic properties has been a challenge. Herein, we report a new bottom-up synthetic method utilizing ammonium fluoride (NH₄F) for the preparation of anhydrous MF_x (CuF₂, FeF₃, and CoF₂)/mesoporous carbon (MSU–F–C) nanocomposites, whereby a series of metal precursor nanoparticles preconfined in mesoporous carbon were readily converted to anhydrous MF_x through simple heat treatment with NH₄F under solventless conditions. We demonstrate the versatility, lower toxicity, and efficiency of this synthetic method and, using XRD analysis, propose a mechanism for the reaction. All MF_x/MSU–F–C prepared in this study exhibited superior electrochemical performances, through conversion reactions, as the cathode for LIBs. In particular, FeF₃/MSU–F–C maintained a capacity of 650 mAh g^–1_FeF3 across 50 cycles, which is ∼90% of its initial capacity. We expect that this facile synthesis method will trigger further research into the development of various nanostructured MF_x for use in energy storage and other applications.