Development of porous sintered-ceramic separators for application in a LiAl/LiClKCl/FeS battery

The procedure for fabrication of porous sintered-ceramic separators and the technical feasibility of using such separators in LiAl/molten LiClKCl/FeS battery cells have been investigated. Processing techniques have been developed to fabricate ∼1.5–2.5 mm thick, ∼35–60% porous, flat, sintered Y₂O₂ and MgO separator plates with sufficient strength to allow handling prior to and during cell assembly. These separators performed successfully in laboratory-scale cells for up to ∼2000 h and 283 cycles, indicating that the concept of a sintered separator, is viable for LiAl/FeS batteries. The particularly attractive features of these separators are potentially low cost, prefabricated form that allows easy cell assembly, and small pore size (average diameter 0.5–1.0 μm) which provides good particle retention. The test results from the sintered-separator cells indicate that Y₂O₂ is probably unsuitable for long-term performance in LiAl/FeS cells because of its reaction with the positive active material. This is in agreement with the recently reported data on cells with Y₂O₂ felt and powder separators. Sintered MgO separators, however, showed good chemical and mechanical stability in the cell environment.