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<p>Delamination and cracking of air electrodes are two mechanical causes to the degradation of high-temperature electrochemical ceramic cells. While compositing negative thermal expansion (NTE) materials can tackle delamination by lowering the thermal expansion coefficient (TEC) of air electrode, it can exacerbate cracking due to large thermal stress between particles of NTE and positive thermal expansion perovskites (PTE). Here, we introduce interfacial oxides to “wedge” the NTE-PTE interface, thereby resisting cracking inside the bulk of the air electrode through reactive calcination at near-melting temperatures. This concept is demonstrated by compositing negative thermal expansive HfW<sub>2</sub>O<sub>8</sub> with Ba<sub>0.5</sub>Sr<sub>0.5</sub>Co<sub>0.8</sub>Fe<sub>0.2</sub>O<sub>3–δ</sub> (perovskite), forming Co<sub>3</sub>O<sub>4</sub>, Fe<sub>3</sub>O<sub>4</sub>, BaHfO<sub>3</sub> and Sr<sub>3</sub>WO<sub>6</sub> as wedging phases. Enhanced bulk modulus (by 102%), hardness (by 138%), and mitigated TEC (reduced by 35%) are simultaneously achieved, which enhances the durability of the air electrode over 40 rigorous thermal cycles between 600 °C and 300 °C, and even with no decay after two years of exposure to ambient air. This method offers an effective strategy for developing mechanical-robust electrodes of high-temperature electrochemical cells.</p>

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Interfacial oxide wedging for mechanical-robust electrode in high-temperature ceramic cells

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年9月30日

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  • Yuan Zhang,
  • Zhipeng Liu,
  • Junbiao Li,
  • Kuiwu Lin,
  • Daqin Guan,
  • Yufei Song,
  • Guangming Yang,
  • Wei Zhou,
  • Jingjie Ge,
  • Minhua Shao,
  • Bin Chen,
  • Meng Ni,
  • Zongping Shao,
  • Heping Xie

摘要

Delamination and cracking of air electrodes are two mechanical causes to the degradation of high-temperature electrochemical ceramic cells. While compositing negative thermal expansion (NTE) materials can tackle delamination by lowering the thermal expansion coefficient (TEC) of air electrode, it can exacerbate cracking due to large thermal stress between particles of NTE and positive thermal expansion perovskites (PTE). Here, we introduce interfacial oxides to “wedge” the NTE-PTE interface, thereby resisting cracking inside the bulk of the air electrode through reactive calcination at near-melting temperatures. This concept is demonstrated by compositing negative thermal expansive HfW2O8 with Ba0.5Sr0.5Co0.8Fe0.2O3–δ (perovskite), forming Co3O4, Fe3O4, BaHfO3 and Sr3WO6 as wedging phases. Enhanced bulk modulus (by 102%), hardness (by 138%), and mitigated TEC (reduced by 35%) are simultaneously achieved, which enhances the durability of the air electrode over 40 rigorous thermal cycles between 600 °C and 300 °C, and even with no decay after two years of exposure to ambient air. This method offers an effective strategy for developing mechanical-robust electrodes of high-temperature electrochemical cells.