Metal Fluoride Cathode Materials for Lithium Rechargeable Batteries: Focus on Iron Fluorides

Abstract

The continued development of modern society is facing the rapid transformation of energy sources from polluting fossil fuels to clean and sustainable energy. Among the available energy storage equipment, lithium-ion (LIBs)/lithium metal batteries (LMBs) have the features of high energy/ power density, long life, and environmental friendliness and have attracted significant academic and industrial attention. Since the successful commercialization of LIBs in the 1990s, the energy density of batteries has been significantly improved. [1] Currently, energy densities of 260-295 Wh kg −1 and 650-730 Wh L −1 have been achieved for 3C (Computer, Communication, and Consumer Electronics) devices. [2,3] Commercial LIBs based on intercalation/insertion-type

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

“…8,9 Despite these outstanding advantages, its practical application is restricted by low conductivity, slow reaction kinetics, and other problems. 10 The solution is usually to nanosize the TMF x compound and to mix or coat it with a large number of conductive carbon materials to improve its electronic conductivity. 11 TMF x /C composites 10,12 that form various nanostructures are examples, e.g., graphene, 13,14 nanocages, 15 nanowires and nanocrystals, 12,16 and nanospheres, 17 or 3D porous nanostructures.…”

“…The solution is usually to nanosize the TMF x compound and to mix or coat it with a large number of conductive carbon materials to improve its electronic conductivity . 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.…”

“…These fluorides show a higher specific capacity and energy density than those of the mainstream intercalation-type cathode materials used in lithium-ion batteries, especially FeF 3 with its high voltage characteristics . The voltage of FeF 3 is higher than 2.74 V vs Li + /Li, and the theoretical specific capacity of 3e – conversion is up to 712 mAh g –1 . , Despite these outstanding advantages, its practical application is restricted by low conductivity, slow reaction kinetics, and other problems . The solution is usually to nanosize the TMF x compound and to mix or coat it with a large number of conductive carbon materials to improve its electronic conductivity .…”

Multicore–shell iron fluoride@carbon microspheres as a long-life cathode for high-energy lithium batteries

“…However, FeF 3 is an electronic and ionic insulator, leading to poor reaction kinetics, large volume change (up to 26%) for lithiation, associated with mechanical stress and electrode fracture and high voltage hysteresis, which all negatively impact its cycling ability and hinder its commercialization as a cathode for LIBs. 7,8 Until now, several strategies have been applied to overcome these issues. Different synthesis methods can have a significant impact on mesoscopic structures.…”

Pyrochlore‐Type Iron Hydroxy Fluorides as Low‐Cost Lithium‐Ion Cathode Materials for Stationary Energy Storage

“…[3][4][5][6] To achieve this goal, iron (III) fluoride-based compounds are being intensely explored as inexpensive cathode active materials for lithium-ion batteries (LIBs). [7][8][9][10][11][12][13] They possess numerous advantages such as an abundance of constituent chemical elements, high lithiation potentials of 2.7-3.1 V versus Li + /Li, and a high theoretical capacity of 237 mA h g −1 for one-electron operation. Iron (III) fluorides with a pyrochlore-type structure (Pyr-FeF 3 ) are of particular interest owing to the presence of large hexagonal channels formed from corner-sharing FeF 6 octahedra.…”