Hierarchical mesoporous iron-based fluoride with partially hollow structure: facile preparation and high performance as cathode material for rechargeable lithium ion batteries.

Hierarchical mesoporous structured iron based fluorides (abbreviated as HMIFs) are successfully synthesized for the first time by a solvothermal method through self-assembly. The fluorides are built from a large amount of nanorods with a size more than a dozen nanometers and exhibit dual phases consisting of Fe1.9F4.75·0.95H2O and FeF3·H2O. A possible formation mechanism is proposed by systematically investigating the synthesis conditions including temperature, reaction time and the amount of the fluorides source. The electrochemical performance of HMIFs as cathodes for rechargeable lithium batteries is investigated. A large reversible capacity exceeding 200 mA h g(-1) without any conducting agent coating and excellent cyclic performance with a residual capacity of 148 mA h g(-1) after 100 cycles are obtained at 0.1 C. In addition, an outstanding rate performance exceeding 100 mA h g(-1) at 5 C highlights the advantages of HMIFs materials for energy storage applications in high-performance LIBs.