TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Method: The method involves depositing the seed layer on the hydrogen membrane cathode electrode by one of spin-coating and dip-coating HAP particles; depositing the seed layer on a non-metallic hydrogen membrane cathode electrode; electrochemically depositing the seed layer on the hydrogen membrane cathode electrode (preferably pure palladium hydrogen membrane cathode electrode). The method involves reducing an amount of evolved hydrogen at the cathode electrode by at least one of applying an electrical current less than or equal to 10 milliampere per square centimeter (mA/cm2) and limiting the deposition time for 5-1 minutes. The step of the secondary crystallization involves controlling supersaturation of HAP to mediate crystal nucleation and growth with one of a calcium ion chelator and a pH regulator. The step of the tertiary crystallization involves controlling the c-axis/a-axis growth by adding a cationic surfactant during the hydrothermal growth of the HAP film; or by varying the ratio of calcium to phosphorus. The method involves adding cetylpyridinium chloride. The step of the tertiary crystallization involves controlling the c-axis/a-axis growth with a crystal growth modifier. The method involves controlling the thickness of the HAP thin film to a thickness of less than or equal to 10 microns by at least one of limiting the electrochemical deposition time to five to one minutes and creating a higher molar ratio of calcium to phosphate during at least one of the hydrothermal depositions. The method involves adding a crystal growth modifier to alter the growth rate of the crystal a-axis relative to the crystal c-axis.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The substrate is a metallic, removable, or sacrificial material; and is a palladium, nickel, or an unsupported thin film, where the palladium substrate includes a porous support. The porous support is stainless steel. The palladium substrate has a thickness of 20-30 microns. The substrate is palladium alloyed with another metal, where another metal includes at least one of silver and copper. The crystalline ion-conducting thin film is hydroxyapatite (HAP). The film thickness is 2-30 (preferably greater than zero to 10) micron. The film thickness (t) is 2-5 micron. The single HAP crystals are rod-shaped. The HAP thin film is free of grain boundaries across the thickness (t). The thin film is hydrothermally-grown and electrochemically-seeded structure that is directly adhered to the substrate. The thin film is yttrium-substituted HAP and fluorine-substituted HAP. The HAP thin film further comprises a sol-gel coating of HAP. The substrate is a palladium alloy. The alloy is one of palladium/silver and palladium/copper. The ion/proton conducting membrane further comprises a cathode material layer on the top surface of the thin film, where the cathode material layer is Ba0.5Sr0.5CO0.8Fe0.2O3- delta (BSCF). The cathode material layer is LaSrCoFeO. The cathode material layer is a metal oxide. The metal oxide is a lithiated nickel oxide (LixNiO2+ (x=0.05-1.0)). The calcium ion chelator comprises one of EDTA and bis(2-ethylhexyl)sulfosuccinate. The pH regulator comprises one of urea and hexamethylenetetramine. The crystal growth modifier is selected from tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetrahexylammonium bromide, tetraoctylammonium bromide, triethanolamine, trimethyl(tetradecyl)ammonium bromide, benzyltriethylammonium chloride, benzyldimethyldodecylammonium chloride, poly(diallydimethylammonium chloride), 1-ethyl-2-methylquinolinium iodide, and cetyltrimethyl ammonium bromide. EXAMPLE - No suitable example given.