Samsung Electronics Co., Ltd. (Suwon-si, KR) and Stanford University (Palo Alto, CA) share U.S. Patent 7,691,523 for a method of preparing an improved solid oxide fuel cell and its membrane electrode assembly using a proton conducting solid perovskite electrolyte containing nano and micro grains of yttrium-doped barium zirconate.
The manufacturing method includes preparing a substrate, forming a buffer layer having a single crystalline structure on the substrate, forming a proton conducting solid perovskite electrolyte membrane on the buffer layer, forming a first electrode on one surface of the proton conducting solid perovskite electrolyte membrane, etching the substrate, and forming a second electrode on the opposite surface of the one surface of the electrolyte membrane.
The method of preparing a fuel cell improves the ion conductivity of an electrolyte membrane at a low temperature and a membrane electrode assembly of a solid oxide fuel cell prepared by the method can improve ion conductivity at a low temperature, according to inventors Joon-Hyung Shim, Sang-kyun Kang, Turgut M. Gur and Friedrich B. Prinz.
The proton conducting solid perovskite electrolyte membrane comprises yttrium-doped barium zirconate (BYZ) and the buffer layer comprises MgO or SrTiO3. The solid oxide electrolyte forms a granular structure which has nano– to micro-meter grain size according to the processing conditions. Ion conductivity in grain boundaries is far less than that in bulk particles.
The figure shows atomic force microscope (AFM) surface images of the thickest (670 nm) and thinnest (60 nm) BYZ membranes.