Abstract
The structural cell components of lithium-aluminum/iron sulfide secondary batteries must combine corrosion resistance with light weight and mechanical strength to maximize battery performance and lifetime. Static corrosion tests and postoperative examination of terminated cells serve to determine the relative compatibility of current collector materials and ceramics insulators. Stainless steel, nickel, and nickel-base alloys have shown suitable corrosion resistance for application as current collectors in FeS electrodes. Low carbon steel has exhibited sufficient intergranular attack to make its long term performance as an FeS electrode current collector doubtful. Molybdenum has demonstrated proven compatibility with the FeS2 electrode environment; however, the sulfidation attack on alloys in this media was extensive. Ceramics that are thermodynamically unstable in contact with lithium were found to fail by rapid deterioration or the formation of a conductive surface layer. Intrinsically stable ceramic materials (e.g., Y2O3, BeO, MgO, ThO2, BN, and AlN) demonstrated good compatibility when the impurity concentrations were held to tolerable levels. With few exceptions, the performance of the tested materials declined with increased temperature over the 400 to 500°C range.