Search

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.

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.