title: Ammonium Fluoride Mediated Synthesis of Anhydrous Metal Fluoride-Mesoporous Carbon Nanocomposites for High-Performance Lithium Ion Battery Cathodes.
abstract: Metal fluorides (MFx) 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 MFx(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 MFxthrough 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 MFx/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-1FeF3across 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 MFxfor use in energy storage and other applications.
authors.forename: Jinyoung
authors.initials: J
authors.lastname: Chun
authors.forename: Changshin
authors.initials: C
authors.lastname: Jo
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798, Republic of Korea.
authors.forename: Sunhye
authors.initials: S
authors.lastname: Sahgong
authors.forename: Min Gyu
authors.initials: MG
authors.lastname: Kim
authors.forename: Eunho
authors.initials: E
authors.lastname: Lim
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798, Republic of Korea.
authors.forename: Dong Hyeon
authors.initials: DH
authors.lastname: Kim
authors.forename: Jongkook
authors.initials: J
authors.lastname: Hwang
authors.forename: Eunae
authors.initials: E
authors.lastname: Kang
authors.forename: Keun Ah
authors.initials: KA
authors.lastname: Ryu
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798, Republic of Korea.
authors.forename: Yoon Seok
authors.initials: YS
authors.lastname: Jung
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan 689-798, Republic of Korea.
authors.forename: Youngsik
authors.initials: Y
authors.lastname: Kim
authors.forename: Jinwoo
authors.initials: J
authors.lastname: Lee
keywords: ammonium fluoride; high-capacity cathodes; lithium ion batteries; metal fluorides; nanocomposites