Department of Mechanical Engineering, University of South Carolina , Columbia, South Carolina 29201, United States.
Nano Lett. 2013 Sep 11;13(9):4340-5. doi: 10.1021/nl402138w. Epub 2013 Aug 12.
We demonstrate that the highly active but unstable nanostructured intermediate-temperature solid oxide fuel cell cathode, La0.6Sr0.4CoO3-δ (LSCo), can retain its high oxygen reduction reaction (ORR) activity with exceptional stability for 4000 h at 700 °C by overcoating its surfaces with a conformal layer of nanoscale ZrO2 films through atomic layer deposition (ALD). The benefits from the presence of the nanoscale ALD-ZrO2 overcoats are remarkable: a factor of 19 and 18 reduction in polarization area-specific resistance and degradation rate over the pristine sample, respectively. The unique multifunctionality of the ALD-derived nanoscaled ZrO2 overcoats, that is, possessing porosity for O2 access to LSCo, conducting both electrons and oxide-ions, confining thermal growth of LSCo nanoparticles, and suppressing surface Sr-segregation is deemed the key enabler for the observed stable and active nanostructured cathode.
我们证明，通过原子层沉积（ALD）在高度活跃但不稳定的纳米结构中温固体氧化物燃料电池阴极 La0.6Sr0.4CoO3-δ（LSCo）表面覆盖一层纳米级 ZrO2 薄膜，可以使其在 700°C 下保持 4000 小时的高氧还原反应（ORR）活性和卓越的稳定性。纳米级 ALD-ZrO2 涂层的存在带来了显著的好处：与原始样品相比，极化面积比电阻降低了 19 倍，降解率降低了 18 倍。ALD 衍生的纳米级 ZrO2 涂层的独特多功能性，即具有氧气进入 LSCo 的多孔性、同时传导电子和氧化物离子、限制 LSCo 纳米颗粒的热生长以及抑制表面 Sr 偏析，被认为是观察到的稳定和活跃的纳米结构阴极的关键促成因素。
