Dual‐Carbon‐Confined Fe₇S₈ Anodes with Enhanced Electrochemical Catalytic Conversion Process for Ultralong Lithium Storage.

Zhang, Yu‐Jiao; Chang, Wei; Qu, Jin; Hao, Shu‐Meng; Ji, Qiu‐Yu; Jiang, Zhi‐Guo; Yu, Zhong‐Zhen

Although the electrochemical catalytic conversion process is effective in increasing the reversible capacity of lithium‐ion batteries, the low contact efficiency between metal catalyst and substrate and pulverization of the solid electrolyte interface (SEI) film without protection are not beneficial for the electrochemical reactions. Herein, Fe7S8 nanoparticles are confined by both reduced graphene oxide (RGO) and in‐situ‐formed amorphous carbon (C) to form dual‐carbon‐confined Fe7S8 as a lithium‐ion anode. The dual‐carbon‐confined structure provides a confined space to prevent pulverization of the SEI film and increases the local concentration of intermediate phases, which could be electrocatalytically decomposed by Fe nanoparticles formed in situ to increase the reversibility of the electrochemical reactions and gain high reversible capacity. In addition, the dual‐carbon‐confined structure ensures fast transfer of electrons and boosts transport of lithium ions due to the highly conductive dual‐carbon shell. Thus, the Fe7S8/C/RGO anode delivers an excellent rate performance and long cycling stability. At current densities of 2000 and 5000 mA g−1, the reversible capacities are 520 mA h g−1 over 1500 cycles and 294 mA h g−1 over 2000 cycles, respectively. Dual confinement: Fe7S8 nanoparticles dually confined by both reduced graphene oxide (RGO) and in‐situ‐formed amorphous carbon (C) were fabricated as Li‐ion battery anodes (see figure). The dual‐carbon‐confined structure prevents pulverization of the solid electrolyte interface film, increases the local concentration of intermediate phases, makes the electrochemical catalytic conversion reaction occur easily, and ensures fast transfer of electrons and increased transport of lithium ions.

ELECTROCHEMISTRY; IRON catalysts; ANODES; LITHIUM ions; METAL catalysts; AMORPHOUS carbon

Chemistry - A European Journal, 2018, Vol 24, Issue 65, p17339

0947-6539

Academic Journal

10.1002/chem.201804221