3D conductive iron fluoride (III) cathode with high loading for lithium-ion batteries

Abstract

The conversion-typed FeF3 cathode with high theoretical capacities seriously suffers from low intrinsic conductivity, sluggish reaction kinetics, and side reactions for lithium ion batteries. Especially, the composites with high loading FeF3 show poor cycling performance. Herein, an effective strategy of the nanoconfinement in the 3D conductive matrix is proposed to address the aforementioned challenges of FeF3. The FeF3 nanoparticles are only 10-50 nm due to the nanoconfined. And the loading of it is as high as 81.89%, which is the highest compared to other composites previous reported. The as-prepared FeF3-CNFs offers high reversible capacities of as high as 313 mAh g-1 at 0.1 C. Moreover, it shows enhanced cycle stability with 88.4% after 100 cycles at 1 C. The improved electrochemical performance is attributed to the 3D conductive network as well as the nanoconfinement of FeF3, which achieve a good capacitance-controlled process by accelerating electron transport while shortening the ion transport path. It is believed that this work provides an efficacious strategy to enhance the electrochemical performance of conversion-typed metal fluoride cathodes for lithium ion batteries.

Optimizing the Electron Spin States of Na4Fe3(PO4)2P2O7 Cathodes via Mn/F Dual‐Doping for Enhanced Sodium Storage

“…[11,13] On the other hand, the results for NFPP-F may seem to contradict Vegard's rule due to the slightly smaller ionic radius of fluorine (1.33 Å) compared to oxygen (1.40 Å). However, this is consistent with the formation of the larger Fe 2+ (0.61 Å) cation from Fe 3+ (0.55 Å) during fluorination, [14,15] as confirmed by the Fe 2p level shown in X-ray photoelectron spectroscopy (XPS) spectra. The proportion of Fe 2+ cations in the as-prepared NFPP, NFPP-Mn, NFPP-F, and NFPP-Mn-F samples was found to be 81.6%, 82.3%, 86.2%, and 86.8%, respectively (Figure S2d, Supporting Information).…”

Boosting the Electrochemical Performance of Primary and Secondary Lithium Batteries with Mn-Doped All-Fluoride Cathodes

“…TMF x /C composites , that form various nanostructures are examples, e.g., graphene, , nanocages, nanowires and nanocrystals, , and nanospheres, or 3D porous nanostructures . Among them, the reported loading mass of the active substance FeF 3 is as high as 81.89%, which means that the remaining 20% is nonelectrochemically active conductive carbon material. This significantly reduces the energy density of the cathode.…”