Li and Li-Al negative electrode characteristics for the lithium secondary battery with a nonflammable SOCl2, Li added, LiCl saturated AlCl3-EMIC molten salt electrolyte

An AlCl3-1-ethyl-3-methylimidazolium chloride (EMIC) melt has a wide electr ochemical window, and it is nonflammable with no ignition. We have develope d the rocking chair type lithium secondary battery with an AlCl3-EMIC melt containing excess LiCl with a saturated solubility as the nonflammable elec trolyte. In this paper, when LiCl was added in the acidic melt (AlCl3 >50 m ol %), the solubility of the LiCl and the changes in the physical propertie s were measured. Moreover, SOCl2 or Li metal was treated to completely remo ve any small amounts of Al2Cl7-, which was the ionic species for deposited Al, that remained in the melt. As a result, it was confirmed that Al2Cl7- w as completely removed based on a cyclic voltammogram (C.V.) using a W elect rode. The reversible deposition and dissolution behavior of lithium was ind icated from the C.V. for a Li electrode in the SOCl2 containing melt, and i t was found that a Li metal would perform as the negative electrode active material.