Detrimental Effect of Sintering Additives on Conducting Ceramics: Yttrium‐Doped Barium Zirconate. Issue 23 (24th October 2018)

• Record Type: Journal Article
• Authors: Han, Donglin; Uemura, Shigeaki; Hiraiwa, Chihiro; Majima, Masatoshi; Uda, Tetsuya
• Is Part Of: ChemSusChem. Volume 11:Issue 23(2018)
• Page Start: 4102
• Page End: 4113
• Publication Date: 2018-10-24
• Subjects: barium zirconate -- electrolytes -- energy materials -- fuel cells -- sintering; Green chemistry -- Periodicals; Sustainable engineering -- Periodicals; Chemistry -- Periodicals; Chemical engineering -- Periodicals; 660
• DOI: 10.1002/cssc.201801837
• Languages: English
• ISSNs: 1864-5631

Abstract

Abstract: Y‐doped BaZrO3 (BZY) is currently the most promising proton‐conductive ceramic‐type electrolyte for application in electrochemical devices, including fuel cells and electrolyzer cells. However, owing to its refractory nature, sintering additives, such as NiO, CuO, or ZnO are commonly added to reduce its high sintering temperature from 1600 °C to approximately 1400 °C. Even without deliberately adding a sintering additive, the NiO anode substrate provides another source of the sintering additive; during the co‐sintering process, NiO diffuses from the anode into the BZY electrolyte layer. In this work, a systematic study of the effect of NiO, CuO, and ZnO on the electroconductive properties of BaZr0.8 Y0.2 O3− δ (BZY20) is conducted. The results revealed that the addition of NiO, CuO, or ZnO into BZY20 not only degraded the electrical conductivity but also resulted in enhancement of the hole conduction. Removal of these sintering additives can be realized by post‐annealing in hydrogen at a mild temperature of 700 °C, but it is kinetically very slow. Therefore, the addition of NiO, CuO, and ZnO is detrimental to the electroconductive properties of BZY20, and significantly restrict its application as an electrolyte. The development of new sintering additives, new anode catalysts, or new methods for preparing BZY electrolyte‐based cells is urgently needed. Abstract : BZY doing something : Sintering additives such as NiO, CuO, or ZnO have a negative effect on the electrochemical properties on Y‐doped BaZrO3 (BZY). NiO also diffuses into BZY from the anode during the conventional co‐sintering process. New processes for the fabrication of cells are in high demand.