title: Metastable Marcasite-FeS2as a New Anode Material for Lithium Ion Batteries: CNFs-Improved Lithiation/Delithiation Reversibility and Li-Storage Properties.
abstract: Marcasite (m-FeS2) exhibits higher electronic conductivity than that of pyrite (p-FeS2) because of its lower semiconducting gap (0.4 vs 0.7 eV). Meanwhile, as demonstrates stronger Fe-S bonds and less S-S interactions, the m-FeS2seems to be a better choice for electrode materials compared to p-FeS2. However, the m-FeS2has been seldom studied due to its sophisticated synthetic methods until now. Herein, a hierarchical m-FeS2and carbon nanofibers composite (m-FeS2/CNFs) with grape-cluster structure was designed and successfully prepared by a straightforward hydrothermal method. When evaluated as an electrode material for lithium ion batteries, the m-FeS2/CNFs exhibited superior lithium storage properties with a high reversible capacity of 1399.5 mAh g-1after 100 cycles at 100 mA g-1and good rate capability of 782.2 mAh g-1up to 10 A g-1. The Li-storage mechanism for the lithiation/delithiation processes of m-FeS2/CNFs was systematically investigated by ex situ powder X-ray diffraction patterns and scanning electron microscopy. Interestingly, the hierarchical m-FeS2microspheres assembled by small FeS2nanoparticles in the m-FeS2/CNFs composite converted into a mimosa with leaves open shape during Li+insertion process and vice versa. Accordingly, a "CNFs accelerated decrystallization-recrystallization" mechanism was proposed to explain such morphology variations and the decent electrochemical performance of m-FeS2/CNFs.
authors.affiliation: Faculty of Chemistry, National & Local United Engineering Laboratory for Power Batteries, Northeast Normal University , Changchun, Jilin 130024, China.
authors.forename: Hong-Hong
authors.initials: HH
authors.lastname: Fan
authors.affiliation: Faculty of Chemistry, National & Local United Engineering Laboratory for Power Batteries, Northeast Normal University , Changchun, Jilin 130024, China.
authors.forename: Huan-Huan
authors.initials: HH
authors.lastname: Li
authors.affiliation: Faculty of Chemistry, National & Local United Engineering Laboratory for Power Batteries, Northeast Normal University , Changchun, Jilin 130024, China.
authors.forename: Ke-Cheng
authors.initials: KC
authors.lastname: Huang
authors.affiliation: Faculty of Chemistry, National & Local United Engineering Laboratory for Power Batteries, Northeast Normal University , Changchun, Jilin 130024, China.
authors.forename: Chao-Ying
authors.initials: CY
authors.lastname: Fan
authors.affiliation: Faculty of Chemistry, National & Local United Engineering Laboratory for Power Batteries, Northeast Normal University , Changchun, Jilin 130024, China.
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: Zhang
authors.affiliation: Faculty of Chemistry, National & Local United Engineering Laboratory for Power Batteries, Northeast Normal University , Changchun, Jilin 130024, China.
authors.forename: Xing-Long
authors.identifier: http://orcid.org/0000-0003-1069-9145
authors.initials: XL
authors.lastname: Wu
authors.affiliation: Faculty of Chemistry, National & Local United Engineering Laboratory for Power Batteries, Northeast Normal University , Changchun, Jilin 130024, China.
authors.forename: Jing-Ping
authors.identifier: http://orcid.org/0000-0001-8004-3673
authors.initials: JP
authors.lastname: Zhang
keywords: FeS2; anode materials; carbon nanofibers; lithium ion batteries; marcasite