3D Conductive Iron Fluoride (III) Cathode with High Loading for Lithium-Ion Batteries


 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.