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

Abstract

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 N2 atmosphere contributes to the fabrication of two shape-maintained FeF3·0.33H2O nanostructures (named O-FeF3·0.33H2O and S-FeF3·0.33H2O, respectively) with confined hierarchical porosity and graphitized carbon skeleton. The lithium storage performances for the MOF-derived octahedral O-FeF3·0.33H2O and spindle S-FeF3·0.33H2O composites are investigated, and the prospective lithium storage mechanism is discussed. As a result, the main product of the porous O-FeF3·0.33H2O 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–1), the capacity attenuation rate of the as-prepared O-FeF3·0.33H2O 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-FeF3·0.33H2O can be confirmed by the Li-ion diffusion coefficient (D Li +) calculation analysis and kinetics analysis of lithium storage behavior.

Recent Advances in Cu-Based Metal–Organic Frameworks and Their Derivatives for Battery Applications

“…Depending on the type of atmosphere exposed, the metal components of MOFs are transformed into alloys, metal oxides, metal sulfides, metal phosphides, and so forth. The organic components of MOFs can directly form carbonaceous materials or can provide heterogeneous atom (such as C, N) doping . This simple transformation method almost preserves the open framework structure of pristine MOFs and forms complex structures of tunable porous or hollow structures and compositions .…”

Recent advances in Fe-based metal–organic framework derivatives for battery applications

“…70,71 Moreover, due to the use of rare and precious metals in plug-in cathodes, the cost is too high to satisfy the growing energy demands of the future. 72 Nonetheless, Fe-MOFderived materials have attracted extensive attention in order to achieve excellent electrochemical efficiency due to their good morphology in the design and development of LIBs. These results indicate that Fe-MOF-derived materials have the potential for practical application in LIBs.…”

“…3a). 72 Interestingly, the nanomaterials prepared using Fe-MOFs with these two structures improve their own electrical conductivity by forming an in situ graphitized conductive carbon skeleton, ensuring their own capacity for further stability. The capacity retention and coulombic efficiency of O–FeF 3 ·0.33H 2 O in the octahedral configuration were better than those of S–FeF 3 ·0.33H 2 O in the spindle form.…”

“…In order to solve these problems, the particle size can be reduced to the nanometer scale by using appropriate methods, or a new kind of layered nanostructure can be constructed. In this way, the diffusion distance of electrolyte ions Scheme 1 The principles and main directions for the structure and synthesis design of Fe-MOF derivatives 58,72,114,140.…”

Metal–organic frameworks and their derivatives as electrode materials for Li-ion batteries: a mini review

“…87 Cheng et al proposed a morphology control strategy based on microwave-assisted tuning of Fe-MOFs to produce octahedral nanostructures O–FeF 3 ·0.33H 2 O and spindle nanostructures S–FeF 3 ·0.33H 2 O, respectively. 88 Among them, the porous octahedral O–FeF 3 ·0.33H 2 O exhibited good electrochemical performance. Even after more than 1000 cycles at a 2C current, the electrode exhibited a capacity decay rate as low as 0.039% per cycle.…”