High-Performance
Co-Free Ruddlesden–Popper-Type
Perovskites by In Situ-Controlled Exsolution-Defined Nanocomposites
for Protonic Ceramic Fuel Cell Cathodes
posted on 2024-02-23, 04:31authored byJian Gong, Lanlan Xu, Wanfeng Zhu, Lei Xie, Xiping Chen, Xiaojuan Liu
Evolving
protonic ceramic fuel cell (PCFC) cathodes require
excellent
oxygen reduction reactivity (ORR), high triple (H+/O2–/e–) conductivity, and adequate
operational stability at intermediate-to-low temperatures. In this
work, a brand new nanocomposite compound was designed by applying
the cathodic surface modification method on A-site-deficient Ruddlesden–Popper-type
(RP) Pr2.7Ni1.6Cu0.3Nb0.1O7‑δ (P2.7NCNO) possessing a triple-conducting
property for PCFC cathodes. This nanocomposite contains the primary
phase of the RP structure, with NiO nanoparticles evenly dispersed
upon its surface. The ORR activity improves with polarization resistance
reaching 0.25 Ω·cm2 at 600 °C. The quick
charge transfer and oxygen surface exchange benefit from the Nb and
Cu codoping and surface NiO nanoparticles based on distribution of
relaxation time (DRT) analysis. Furthermore, P2.7NCNO exhibits higher
proton conductivity under different atmospheres owing to Nb and Cu
codoping. Excellent results are observed at 600 °C when used
as the cathode in PCFC single cells, achieving a peak power density
of 1024 mW·cm–2. Moreover, the P2.7NCNO sample
exhibits appropriate endurance durability (600 mA·cm–2 at 600 °C for ∼130 h) and acceptable thermal compatibility
with proton conductor electrolytes BaZr0.1Ce0.7Y0.1Yb0.1O3‑δ (BZCYYb)
thanks to the Co-free structure. These results demonstrate that the
surface modification strategy of proper composition manipulation on
the RP structure provides useful guidance for future study and optimization
for intermediate-to-low-temperature PCFC cathodes.