Synthesis and charge-discharge properties of 2LiF-NiF₂ composite and Li₂NiF₄ as a cathode material for Li-ion batteries.

Abstract

2LiF-NiF2 composites are synthesized by the mechanical milling of LiF and NiF2 in a molar ratio of 2 : 1 for 72 h, and Li2NiF4 are synthesized by calcination at 673 K. The synthesized samples are investigated by XRD, cyclic voltammetry, and charge-discharge measurements. XRD peaks of the 2LiF-NiF2 composite are broad and the discharge capacity is 44 mAh/g at 0.05 C for voltages of 2.0-4.8 V. After calcination, the XRD peaks become sharp and most peaks are agreement with Li2NiF4. Li2NiF4 obtained by calcination shows a discharge capacity of 96 mAh/g at 0.05 C and 118 mAh/g at 0.02 C for voltages of 2.0-4.8 V. 2LiF-NiO composites are also obtained by the milling of LiF and NiO in a molar ratio of 2 : 1 for 72 h, and shows a discharge capacity of 146 mAh/g. The discharge capacity of 2LiF-NiO at 3C was maintained that of 70 % of 0.1C.

Fluorinated Materials as Positive Electrodes for Li- and Na-Ion Batteries

“…The initial capacity was lower but remained at a good level of 303 mAh g –1 after 40 cycles . Li 2 NiF 4 was also obtained by the mechanical milling of LiF and NiF 2 in a 2:1 molar ratio for 72 h, and calcination at 673 K; it shows a discharge capacity of 96 mAh g –1 at C/20 and 118 mAh g –1 at C/50 in the range 2.0–4.8 V. Prepared by the same synthesis technique, 2LiF-NiO composites show a discharge capacity of 146 mAh g –1 at C/10 …”

“…166 Synthesized by the TFA sol−gel route, Li 2 NiF 4 exhibits a large capacity drop from 756 to 40 mAh g −1 after only 20 cycles. 167 The very poor reversibility, linked to the formation 169 For in situ elaboration, a surface fluorination process during charging with MnO as the active cathode material triggered by the decomposition of the electrolyte LiPF 6 , resulted in the formation of core−shell oxyfluoride particles. The spinel type core was oxygen-rich, while the fluorine-rich shell was amorphous.…”

Synthesis of MnO-LiF Composite Cathode Material Using NH4F as a fluorine source

“…Recently, the discovery of a new class of non-intercalation cathode materials based on nanocomposites of alkali metal compounds (i.e., LiF) and Li-free transition metal compounds (i.e., MnO and FeF 2 ) with transition metal in the intermediate oxidation state, was reported [9][10][11][12][13][14][15][16][17][18][19][20][21]. These nanocomposites not only donate lithium ions to the anode but also show high speci c capacities and high redox voltages.…”