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Fluorinated, manganese‐redox cation‐disordered rocksalts are promising candidates for high‐performance cobalt‐free Li‐ion cathode active material. A need for reactive fluorinated precursors was however identified. While manganese oxyfluorides are promising precursor candidates, none stable at room temperature was reported prior to 2023. The key to their recent synthesis by reacting molecular fluorine with MnO was a procedure to continuously scan the temperature axis in search of activation temperatures. In line with this philosophy of continuous exploration of the chemical space, two experimental procedures are reported to scan the stoichiometry axis of a gas‐solid phase diagram in search of transitions and intermediate compounds. Their application to F2 ‐ Mn3O4 and F2 ‐ Mn2O3 phase diagrams resulted in the discovery of two new ranges of stable manganese oxyfluorides of respective compositions MnO1.33‐0.13xFx with x<0.5 and MnO1.5‐0.22xFx with x<1. [ABSTRACT FROM AUTHOR]

Little is known about room-temperature fluoride-ion batteries (RT FiBs), and no investigations that have varied their potential electrolytes, cathode preparations, or anode materials have been reported. In this publication, an overview of our recent investigations of these parameters for the purposes of improving the discharge capacities of RT FiBs is provided. The poly(ethylene glycol) (PEG)-based electrolytes in these systems function as ligands for fluoride ions. The impact of the increasing ligand length on battery capacity was investigated. Using Mg as an anode, different anode builds (e.g., foil or pressed pellets), as well as several composite anodes (e.g., Mg/MgF2) were tested. Furthermore the difference between cathodes prepared as hand-spread slurries or by spray-coating was investigated. Additionally the impact of using a water-soluble binder was examined. Finally, problems due to the leaching of alkaline (and/or alkaline earth) metal ions from the glass-fiber separators into the electrolyte were considered. In summary, it was demonstrated that FiBs will work using magnesium anodes, and that the capacities of such batteries are sensitive to every small change in their components. [ABSTRACT FROM AUTHOR]

One of the problems that arise with bifluoride- or fluoride-containing compounds is their poor solubility in non-aqueous solvents. We report herein a facile one-pot synthesis and the chemical analysis of fluoride/bifluoride-containing polymers, which are soluble in MeCN. Different polymers, such as Polyvinylacetate or Polyethylene imine and saccharides, such as maltodextrin, were complexed with ammonium (bi)fluoride using hydrogen bonds to form the desired (bi)fluoride-containing compounds. The newly formed hydrogen bonding (bi)fluoride-doped polymer matrices were analyzed using infrared and nuclear magnetic resonance spectroscopies, and X-ray diffraction. The promising materials also underwent impedance spectroscopy, conductivity measurements and preliminary tests as electrolytes for room temperature fluoride ion batteries along with an analysis of their performance.