Kim Junseok, Islam Subrina, Bao Yue, Ding Hanping, Duan Chuancheng
Department of Chemical Engineering, University of Utah, Salt Lake City, Utah 84112, United States.
Department of Mechanical Engineering, University of Oklahoma, Norman, Oklahoma 73019, United States.
ACS Appl Mater Interfaces. 2025 Jun 11;17(23):34277-34283. doi: 10.1021/acsami.5c06739. Epub 2025 Jun 2.
Proton ceramic electrochemical cells (PCECs) offer significant advantages for operation at intermediate-to-low temperature operation (≤600 °C), but their development is hindered by the challenge of achieving a fully dense electrolyte without compromising the hydrogen electrode's high active surface area. The extensively studied electrolyte BaCeZrYYbO (BCZYYb4411) is widely known for its high proton conductivity and excellent chemical stability. However, it typically requires high sintering temperatures (≥1550 °C) to achieve full densification, but such high temperatures cause barium volatilization, reduced ionic conductivity, and significantly decrease the active surface area of the hydrogen electrode. Conversely, lower sintering temperatures (<1450 °C) maintain electrode activity but result in incomplete densification, hindering the formation of thin-film electrolytes. This inherent trade-off between electrolyte densification and hydrogen electrode area limits the effectiveness of conventional approaches, including cosintering with the hydrogen electrode, using additional sintering aids, or employing nanoparticles, which often lead to stoichiometric deviations, reduced conductivity, or scalability issues. To address these challenges, we optimized the PCEC fabrication approach by implementing a two-step sintering (TSS) process. This method begins with a brief, high-temperature hold to achieve rapid electrolyte densification, followed by a prolonged hold at a lower temperature to promote grain growth and minimize barium volatilization. Our results demonstrate that the TSS process simultaneously produces a fully dense, stoichiometric electrolyte and a highly porous, active hydrogen electrode. PCECs fabricated using this optimized approach exhibit 1.42-2.10 times higher electrochemical performance at 600 °C compared to those produced via conventional sintering methods. These findings highlight two-step sintering as a promising strategy for improving both electrolyte and hydrogen electrode performance in PCECs.
质子陶瓷电化学电池（PCEC）在中低温运行（≤600°C）方面具有显著优势，但其发展受到挑战，即在不影响氢电极高活性表面积的情况下实现完全致密的电解质。广泛研究的电解质BaCeZrYYbO（BCZYYb4411）以其高质子传导率和优异的化学稳定性而闻名。然而，通常需要高温烧结（≥1550°C）才能实现完全致密化，但如此高的温度会导致钡挥发、离子传导率降低，并显著降低氢电极的活性表面积。相反，较低的烧结温度（<1450°C）可保持电极活性，但会导致致密化不完全，阻碍薄膜电解质的形成。电解质致密化和氢电极面积之间的这种内在权衡限制了传统方法的有效性，包括与氢电极共烧结、使用额外的烧结助剂或采用纳米颗粒，这些方法往往会导致化学计量偏差、传导率降低或可扩展性问题。为应对这些挑战，我们通过实施两步烧结（TSS）工艺优化了PCEC的制造方法。该方法首先进行短暂的高温保温以实现快速的电解质致密化，然后在较低温度下进行长时间保温以促进晶粒生长并最大限度地减少钡挥发。我们的结果表明，TSS工艺同时产生了完全致密的化学计量电解质和高度多孔的活性氢电极。与通过传统烧结方法生产的PCEC相比，使用这种优化方法制造的PCEC在600°C时的电化学性能高出1.42 - 2.10倍。这些发现突出了两步烧结作为一种有前景的策略，可用于提高PCEC中电解质和氢电极的性能。
