Sc-doped BaZrO3 (IMAGE)
Caption
This figure shows the crystal structure of Sc-doped BaZrO3 to be used as an electrolyte material in intermediate temperature solid oxide fuel cells (IT-SOFCs). By using a nuclear magnetic resonance (NMR) technique, the distribution of proton and oxygen vacancy in Sc-doped BaZrO3 was clarified. Green, blue, purple and red spheres represent Ba, Zr, Sc cations and oxide ions in the Sc-doped BaZrO3, respectively. In this material, a proton (gold sphere) having one positive charge is known to be trapped around the Sc cation (purple sphere) since the Sc site possesses one negative charge; the trapped proton is the cause of low proton conductivity at the intermediate temperature range. Meanwhile, when an oxide ion (red sphere) is vacant (center position in this case), the pair of the vacancy and Sc now possesses one positive charge. The positive charge works to liberate the trapped proton from nearby Sc to nearby Zr (blue sphere). This change in proton distribution is believed to improve the proton conductivity of Sc-doped BaZrO3.
Credit
Hitoshi Takamura
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Credit: Hitoshi Nakamura
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