An ideal solid oxide fuel cell (SOFC) cathode should meet multiple requirements, i.e., high activity for oxygen reduction reaction (ORR), good conductivity, favorable stability, and sound thermo‐mechanical/chemical compatibility with electrolyte, while it is very challenging to achieve all these requirements based on a single‐phase material. Herein, a cost‐effective multi‐phase nanocomposite, facilely synthesized through smart self‐assembly at high temperature, is developed as a near‐ideal cathode of intermediate‐temperature SOFCs, showing high ORR activity (an area‐specific resistance of ≈0.028 Ω cm² and a power output of 1208 mW cm⁻² at 650 °C), affordable conductivity (21.5 S cm⁻¹ at 650 °C), favorable stability (560 h operation in single cell), excellent chemical compatibility with Sm_0.2Ce_0.8O_1.9 electrolyte, and reduced thermal expansion coefficient (≈16.8 × 10⁻⁶ K⁻¹). Such a nanocomposite (Sr_0.9Ce_0.1Fe_0.8Ni_0.2O_3–δ) is composed of a single perovskite main phase (77.2 wt%), a Ruddlesden–Popper (RP) second phase (13.3 wt%), and surface‐decorated NiO (5.8 wt%) and CeO₂ (3.7 wt%) minor phases. The RP phase promotes the oxygen bulk diffusion while NiO and CeO₂ nanoparticles facilitate the oxygen surface process and O²⁻ migration from the surface to the main phase, respectively. The strong interaction between four phases in nanodomain creates a synergistic effect, leading to the superior ORR activity.

中文翻译：

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智能自组装开发的无钴多相纳米复合材料，作为中温固体氧化物燃料电池的近乎理想的阴极。

理想的固体氧化物燃料电池（SOFC）阴极应满足多种要求，即氧还原反应（ORR）的高活性，良好的电导率，良好的稳定性以及与电解质的良好的热机械/化学相容性，而对基于单相材料满足所有这些要求。本文中，开发了一种经济高效的多相纳米复合材料，该材料通过高温智能自组装轻松合成，作为中温SOFC的近理想阴极，显示出高ORR活性（约0.028Ω的面积比电阻） cm ²和在650°C下的输出功率为1208 mW cm ^-2），可承受的电导率（21.5 S cm ^-1在650°C下的温度），良好的稳定性（单电池运行560小时），与Sm _0.2 Ce _0.8 O _1.9电解质的化学相容性优异，并且热膨胀系数降低（≈16.8×10 ^-6 K ^-1）。这种纳米复合材料（Sr _0.9 Ce _0.1 Fe _0.8 Ni _0.2 O _{3– δ}）由单个钙钛矿主相（77.2 wt％），Ruddlesden-Popper（RP）第二相（13.3 wt％）组成，并经过表面装饰NiO（5.8 wt％）和CeO ₂（3.7 wt％）次相。RP相促进了氧的体积扩散，而NiO和CeO ₂纳米粒子分别促进了氧表面过程和O ^2-从表面迁移至主相。纳米域中四个相之间的强相互作用产生协同效应，从而导致卓越的ORR活性。