Mediator Catalyst for Lithium Fluoride Decomposition toward Lithium Recovery

A catalyst to electrochemically decompose lithium fluoride (LiF), which is abound in the electrode of the spent LiBs, was studied to develop a Li reproduction technology. Since the oxidizing activity of halogen increases in turn I2, Br2, Cl2, and F2, a reaction I2 +2LiF→F2 + 2LiI cannot proceed. We examined a catalytic activity of interhalogen such as iodine monobromide (IBr) and iodine chloride (ICl) for LiF decomposition in specific organic solvents. We observed chemical decomposition of LiF in IBr and ICl dimethylsulfoxide (DMSO) solutions. This decomposition was induced by an increase in solution acidity, accompanied by large deviation of the electric charge between two halogen elements due to the complex formation of interhalogen with DMSO. A double-chamber type cell for Li recovery from LiF was constructed by combining this LiF decomposition behavior with redox coupling of IBr or ICl operated by electrical charging. The cell was first demonstrated to be chargeable due to the continuous decomposition...