Advancing fluoride-ion batteries with a Pb-PbF2 counter electrode and a diluted liquid electrolyte

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.

In the paper 'Advancing fluoride-ion batteries with a Pb-PbF₂ counter electrode and a diluted liquid electrolyte' published in ACS Energy Letters, Giulia Galatolo headed a team from this department who report a reliable Pb-PbF₂ counter electrode that enabled the use of two-electrode coin cells.  To test this set-up, the authors 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).  They then demonstrate the viability of the system by reporting a BiF₃-Pb-PbF₂ cell with the highest capacity retention to date.