A Novel Silver Molybdenum Oxyfluoride Perovskite as a Cathode Material for Lithium Batteries

Abstract

Novel electroactive nanostructured silver molybdenum oxyfluoride (SMOF) perovskites Ag1+ 3Mo6+(O3F3) have been successfully synthesized by a mechanochemical reaction. The formation of this perovskite was investigated throughout the Ag−Mo composition range with the use of either Ag1+ or Ag2+ in the form of AgF and AgF2 as the reactant, respectively. The compositional study combined with X-ray diffraction and extensive Raman investigation was utilized to determine structure and cation distribution and infer oxidation state. Finally, preliminary electrochemical characterization of the perovskites vs lithium was investigated.

Electrochemically active silver molybdenum oxyfluoride perovskite: Synthesis and in situ electrochemical characterization

“…As described in the previous paper [7], the SMOF perovskite remained as the significant phase in a wide range of AgF-MoO 3 compositions (x = 1. [5][6][7][8][9]. Consistent with the idealized stoichiometry, the maximum phase intensity of the perovskite is obtained at x = 3 relative to the minimal quantity of Mo-or Agcontaining minor phases.…”

“…Preliminary electrochemical evaluation of SMOF electrode indicated that close to theoretical capacity of 5 inserted Li + was achieved with 3 plateaus at 3.6, 3.1 and 2.1 V when discharged to 1.5 V. Our earlier work [7] on an in situ electrochemical study by XRD suggested the insertion of the 3 Li + at the 1st plateau (>3 V) was consistent with the displacement, or possible conversion reaction, of SMOF to Ag metal. However, very little useful information Fig.…”

“…The perovskite phase was also affirmed by the observation of the characteristic Raman active bands around 876 and 380 cm −1 associated to the stretching (S) and bending (B) vibration mode of MoX 6 octahedron on Fig. 2 as described in more detail in our earlier publication [7]. The apparent shift of the vibration band related to the bending MoX 6 octahedron at x > 4 could be due to a distortion of the MoX 6 octahedron or the development of a second phase.…”

“…Recently, we have identified a new compound, silver molybdenum oxyfluoride (SMOF) cryolite-like perovskite, of the proposed formula Ag 3 1+ Mo 6+ (O 3 F 3 ) via mechanochemical synthesis through the use of silver fluorides and molybdenum oxides [6,7]. Preliminary electrochemical characterization showed that the electroactivity of SMOF perovskite was enabled even without the use of conductive carbon matrix, suggesting the as-fabricated SMOF perovskite has appreciable mixed conductivity.…”

Direct Synthesis of Chromium Perovskite Oxyhydride with a High Magnetic‐Transition Temperature

“…[3] However, increasing attention has been paid to mixed-anion perovskites, such as oxyfluorides ABO 2 F and oxynitrides ABO 2 N as promising alternative materials in pigments, [4] watersplitting photocatalysis, [5] dielectric properties, [6] and cathode material. [7] Their properties arise from the substitution of oxygen with other anions as well as the fine tuning of the anionic and interacting d bands of the octahedral center B.…”