CFx Derived Carbon–FeF₂ Nanocomposites for Reversible Lithium Storage

Supercritical-fluid synthesis of FeF2 and CoF2 Li-ion conversion materials

“…A degree of capacity fading was evident over the first four cycles, however, some stabilisation of capacity was 60 attained notably over the first 15 cycles at ~ 300 mAh g -1 , while a discharge capacity of ~ 220 mAh g -1 was returned following 25 charge-discharge cycles, representing a final conversion of approximately 1.1 Li + per formula unit FeF2. Such capacities are largely similar to C-FeF2 nanocomposites discharged to 1.3 V 65 after the same number of cycles, 16 and still superior to theoretical capacities exhibited by some of the more conventional intercalation hosts, e.g., LiCoO2 (~ 120 mAh g -1 ) and LiFePO4 (~ 170 mAh g -1 ); the lower average working voltage and low current rate of FeF2 remains, however, potentially significant.…”

“…In addition, the rate capability of FeFx-based electrodes, owing to their intrinsically poor conductivity and the relatively limited 80 kinetics of the conversion sequence, is also an issue facing the utilisation of FeFx and other similar conversion candidates. The data reported in this work so far was collected at the relatively low specific currents of 10 and 20 mA g Although the conversion kinetics of FeF2 are demonstrated to be cumbersome at room temperature, both Reddy 16 and Badway et al 10 have shown a vast improvement of an equivalent carbon-composite FeF2 cathodes operating at 40 and 70 °C, repectively. ; see table 1), resulting in potentially high energy densities exceeding 1500 Wh kg -1 .…”

In situ generated FeF 3 in homogeneous iron matrix toward high-performance cathode material for sodium-ion batteries

“…Metal fluorides, as one of the most important family of functional inorganic materials, have numerous applications in the field of catalysts, optical devices, and magnetic materials as well as potential cathode materials in LIBs, due to their high theoretical capacity, low cost, abundant sources, low toxicity, and high safety, which are crucial for large-scale electrochemical energy storage [22][23][24][25][26][27]. In addition, they are better choice for Li/Na-polymer batteries which use metal Li/Na as anode.…”

Effects of Steel Cell Components on Overall Capacity of Pulsed Laser Deposited FeF2Thin Film Lithium Ion Batteries

“…Previous investigations of FeF 2 as a cathode material in lithium ion cells have resulting in measured capacities ranging from 130 mAh/g to near theoretical capacity with the large range in measured capacities generally being attributed to differences in FeF 2 processing or cycling conditions. 8,[13][14][15][16] FeF 2 films deposited by PLD reported an increase in capacity upon cycling which was attributed to the oxidation of Fe due to the contamination of oxygen from the electrolyte. The increase in capacity was also postulated to be due to formations of a SEI layer caused by electrolyte decomposition.…”

“…4 that the measured cycling behavior of the FeF 2 films was influenced by cell construction. Previous authors have identified peaks at 3 V during charging and 1.75 V during discharge for FeF 2 cathodes, 8,13,14,33 consistent with what was observed in both the coin cell and aluminum lead pouch cells but in the case of stainless steel lead pouch cells, a distinct peak is observed in the cyclic voltammograms in Fig. 4a at 2 V. The results of the galvanostatic test (capacity vs. cycle number and the corresponding discharge-charge curves) of 130 nm FeF 2 films using stainless steel and aluminum lead pouch cells as well as the coin cell configuration is shown in Fig.…”