title: Beyond yolk-shell nanoparticles: Fe3O4@Fe3C core@shell nanoparticles as yolks and carbon nanospindles as shells for efficient lithium ion storage.
abstract: To well address the problems of large volume change and dissolution of Fe3O4 nanomaterials during Li(+) intercalation/extraction, herein we demonstrate a one-step in situ nanospace-confined pyrolysis strategy for robust yolk-shell nanospindles with very sufficient internal void space (VSIVS) for high-rate and long-term lithium ion batteries (LIBs), in which an Fe3O4@Fe3C core@shell nanoparticle is well confined in the compartment of a hollow carbon nanospindle. This particular structure can not only introduce VSIVS to accommodate volume change of Fe3O4 but also afford a dual shell of Fe3C and carbon to restrict Fe3O4 dissolution, thus providing dual roles for greatly improving the capacity retention. As a consequence, Fe3O4@Fe3C-C yolk-shell nanospindles deliver a high reversible capacity of 1128.3 mAh g(-1) at even 500 mA g(-1), excellent high rate capacity (604.8 mAh g(-1) at 2000 mA g(-1)), and prolonged cycling life (maintaining 1120.2 mAh g(-1) at 500 mA g(-1) for 100 cycles) for LIBs, which are much better than those of Fe3O4@C core@shell nanospindles and Fe3O4 nanoparticles. The present Fe3O4@Fe3C-C yolk-shell nanospindles are the most efficient Fe3O4-based anode materials ever reported for LIBs.
authors.affiliation: †College of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, People's Republic of China.
authors.forename: Jianan
authors.initials: J
authors.lastname: Zhang
authors.affiliation: †College of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, People's Republic of China.
authors.forename: Kaixi
authors.initials: K
authors.lastname: Wang
authors.affiliation: †College of Materials Science and Engineering, Zhengzhou University, Zhengzhou 450052, People's Republic of China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Xu
authors.affiliation: §National Analytical Research Center of Electrochemistry and Spectroscopy, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, People's Republic of China.
authors.forename: Yunchun
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: ∥Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300071, People's Republic of China.
authors.forename: Fangyi
authors.initials: F
authors.lastname: Cheng
authors.affiliation: ‡Physical Chemistry and Applied Spectroscopy, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
authors.forename: Shaojun
authors.initials: S
authors.lastname: Guo
keywords: core−shell structure; iron carbonide; iron oxide; lithium ion battery; yolk−shell structure