Advancing Fluoride-Ion Batteries with a Pb-PbF<sub>2</sub> Counter Electrode and a Diluted Liquid Electrolyte
Giulia Galatolo, Omar Alshangiti, Camilla Di Mino, Guillaume Matthews, Albert W. Xiao, Gregory J. Rees, Maximilian Schart, Yvonne Chart, Lorenz F. Olbrich, Mauro Pasta
Abstract
High Resolution Image Download MS PowerPoint Slide Fluoride ion batteries (FIB) are a promising post lithium-ion technology thanks to their high theoretical energy densities and Earth-abundant materials. However, the flooded cells commonly used to test liquid electrolyte FIBs severely affect the overall performance and impede comparability across different studies, hindering FIB progress. Here, we report a reliable Pb-PbF 2 counter electrode that enables the use of two-electrode coin cells. To test this setup, we first introduce a liquid electrolyte that combines the advantages of a highly concentrated electrolyte (tetramethylammonium fluoride in methanol) while addressing its transport and high-cost shortcomings by introducing a diluent (propionitrile). We then demonstrate the viability of this system by reporting a BiF 3 –Pb-PbF 2 cell with the highest capacity retention to date.