Synthesis and electrochemical properties of 4LiF-NiMn 2 O 4 composite as a cathode material for Li-ion batteries

Lithium manganese oxyfluoride as a new cathode material exhibiting oxygen redox

“…Other researchers have managed to access solid solution oxyfluoride Rocksalt phases by using higher ball-milling energies. In pioneering work by Hahn and Kobayashi and their respective co-workers, lithiated oxyfluoride materials were synthesised based on V [27][28][29] and Ni 30,31 ; two transition metals which undergo multiple valence state changes. However, these have involved prolonged reaction times of over 100 hrs and impurities introduced from abrasion of the milling jar medium.…”

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

“…LiF and NiF2 peaks were observed except for NiF2 (001) diffraction peak for these composites as shown in Figure 1 (a) and (b). In our studies on other composites, it has been shown that the diffraction peaks are broadened due to crystal distortion by long-time milling and that the structure became similar to the rocksalt type from the original structure [15,16]. It is considered that the diffraction peaks became broad and NiF2 (001) peak disappeared due to similar change in NiF2.…”

V2O3–Li3PO4 Composite: A New Type of Cathodic Active Material for Li‐Ion Batteries

“…

state)-LiF or FeF 2 -LiF nanocomposites not only donate lithium ions to the anode but also exhibit high specific capacities and high voltages, functioning as cathodic active materials. [9][10][11][12][13][14][15][16][17] By comparison with the conventional lithium intercalation/ de-intercalation reaction, this peculiar electrochemical behavior is ascribed to a surface conversion reaction.Although the surface conversion reaction has made the M x O y -LiF system a lithiated cathode with encouraging high specific capacity for next-generation LIBs, many challenges remain to be overcome. For example, the high upper limit charging voltage of ≈4.8 V is needed to drive the redox reaction and the breaking of Li-F bond during charging, [9][10][11] which is not compatible with the extensively utilized carbonate electrolytes in the LIBs industry, seldom operated over 4.3 V. To reduce the charge voltage, it is crucial to further lower the activation energy barrier in the process of the surface redox between LiF and M x O y .

…”

“…[9][10][11][12][13][14][15][16][17] By comparison with the conventional lithium intercalation/ de-intercalation reaction, this peculiar electrochemical behavior is ascribed to a surface conversion reaction.Although the surface conversion reaction has made the M x O y -LiF system a lithiated cathode with encouraging high specific capacity for next-generation LIBs, many challenges remain to be overcome. For example, the high upper limit charging voltage of ≈4.8 V is needed to drive the redox reaction and the breaking of Li-F bond during charging, [9][10][11] which is not compatible with the extensively utilized carbonate electrolytes in the LIBs industry, seldom operated over 4.3 V. To reduce the charge voltage, it is crucial to further lower the activation energy barrier in the process of the surface redox between LiF and M x O y . Additionally, the M x O y -LiF system, which was conventionally prepared via mechanical milling, did not exhibit satisfactory properties due to inhomogeneous spatial distribution and loose interfacial contact between LiF and M x O y .Here, to the best of our knowledge, a novel strategy is suggested for the first time to use V 2 O 3 -Li 3 PO 4 composite as a cathodic active material for LIBs, which was synthesized by spray drying and subsequent heat treatment.…”