Nanostructured Iron Fluoride Derived from Fe-Based Metal-Organic Framework for Lithium Ion Battery Cathodes.

A comprehensive strategy for the morphological control of octahedral and spindle Fe-based metal-organic frameworks (Fe-MOFs) via microwave-assisted adjustment is proposed in this research. Afterward, in situ copyrolysis under N atmosphere contributes to the fabrication of two shape-maintained FeF·0.33HO nanostructures (named O-FeF·0.33HO and S-FeF·0.33HO, respectively) with confined hierarchical porosity and graphitized carbon skeleton. The lithium storage performances for the MOF-derived octahedral O-FeF·0.33HO and spindle S-FeF·0.33HO composites are investigated, and the prospective lithium storage mechanism is discussed. As a result, the main product of the porous O-FeF·0.33HO structure is found to be a promising cathode material for lithium ion batteries owing to its advantageous electrochemical capability. Even after being cycled over 1000 times at 2 C (1 C = 237 mAh g), the capacity attenuation rate of the as-prepared O-FeF·0.33HO electrode is as low as 0.039% per cycle. The combination of proper octahedral morphology and highly graphitized carbon modification can not only enhance the conductivity of the cathode but also promote the diffusion of Li effectively. The remarkable performance of octahedral O-FeF·0.33HO can be confirmed by the Li-ion diffusion coefficient () calculation analysis and kinetics analysis of lithium storage behavior.