| abstract |
The present invention relates to solid materials for use as electrolyte for a fuel cell, or for a sensor, or as a catalyst. Representative structures include lanthanum fluoride, lead potassium fluoride, lead bismuth fluoride, lanthanum strontium fluoride, lanthan strontium lithium fluoride, calcium uranium, cesium fluoride, PbSnFy, KSn2F4, SrCl2.KCl, LaOF2, PbSnF8.PbSnO, lanthanum oxyfluoride, oxide, calcium fluoride, SmNdFO, and the like. In another aspect, the present invention relates to a composite and a process to obtain it of the formula: A1-yByQO3 having a perovskite or a perovskite-type structure as an electrode catalyst in combination with: AyB1-yF2+y as a discontinuous surface coating solid electrolyte solid electrolyte wherein A is independently selected from lanthanum, cerium, neodymium, praseodymium, and scandium, B is independently selected from strontium, calcium barium or magnesium, Q is independently selected from nickel, cobalt, iron or manganese, and y is between about 0.0001 and 1, which process comprises: (a) obtaining a particulate of: A1-yByQO3 wherein A, B and y are defined hereinabove having an average size distribution of between about 50 and 200 Angstroms in diameter; (b) reacting the particle of step (a) with a vapor comprising: AyB1-yF2+y wherein A, B and y are defined hereinabove, at about ambient pressure at between about 0 DEG and 1000 DEG C.: for between about 10 and 30 hr. obtain a composite of between about 25 to 1000 microns in thickness; (c) recovering the composite of step (b) having multiple interfaces between the electrode and electrolyte. In another aspect the invention relates to the heating of these solid materials with oxygen and water to obtain higher ionic conductivity. In another aspect the invention relates to the electrochemical doping of oxide ions present by treatment of the electrode-lanthanum fluoride interface at between about 0 DEG and 400 DEG C. in an oxygen environment at between about 10-3 and 10-6 amperes per square centimeter for between about 1 and 60 minutes. The invention also includes the use of the fuel cells disclosed to generate electricity. |