With high energy density both by weight and volume, ammonia (NH₃) is a promising hydrogen carrier. Furthemore, NH₃ has a mature industrial background, and in liquid form storage and transportation is not a problem. Adding the merit of zero CO₂ emission, NH₃-to-power by direct ammonia solid oxide fuel cells (DA-SOFCs) is an acceptable strategy to facilitate hydrogen usage. Nonetheless, to achieve efficacy, a high compatibility between operating temperature and catalytic materials for NH₃ decomposition is needed. In this work, we developed a tubular DA-SOFC with an output power capability of > 3 W. By combining experimental measurements and multi-physics simulation, we comprehensively studies the related intrinsic processes. Based on experimental data, we developed a two-dimensional multi-scale electro-thermo model of tubular DA-SOFC. Separately we evaluated the effects of inlet fuel gas composition, inlet flow velocity, operating temperature, and operating voltage on the rate of NH₃ catalytic decomposition and H₂ electrochemical oxidation, as well as on NH₃ conversion, H atom utilization, and electrical efficiency of the tubular DA-SOFC. The results suggest that high H atom utilization could be realized by matching the rate of NH₃ decomposition with that of H₂ electrochemical oxidation. It was observed that with the decrease of temperature, the rate of H₂ oxidation decreases more rapidly than that of NH₃ decomposition, suggesting that the flow velocity of NH₃ should be appropriately lowered to optimize H atom utilization. Finally, we established a correlation between H atom utilization, operating voltage, and electrical efficiency for synergistic optimization of operating conditions. At 0.7 V and 800 ℃, the tubular DA-SOFC fueled with NH₃ of 27 mL·min⁻¹ is capable of offering 3.2 W, displaying an efficiency of 60%. Compared to that of a tubular H₂-SOFC (only 51% efficiency), the efficiency is significantly higher on the basis of equal voltage and fuel utilization ratio. The outcome of the present study demonstrates the potential of tubular DA-SOFC as a device for high-efficiency power generation.

氨（NH ₃）具有高的重量和体积能量密度，是一种很有前途的氢载体。此外，NH ₃具有成熟的工业背景，液态储存和运输不成问题。通过直接氨固体氧化物燃料电池 (DA-SOFC)添加零 CO ₂排放、NH ₃到电力的优点是促进氢使用的可接受策略。尽管如此，为了实现功效，操作温度和 NH ₃催化材料之间的高度兼容性需要分解。在这项工作中，我们开发了一种输出功率能力 > 3 W 的管状 DA-SOFC。通过结合实验测量和多物理场模拟，我们全面研究了相关的内在过程。基于实验数据，我们开发了管状 DA-SOFC 的二维多尺度电热模型。我们分别评估了入口燃气组成、入口流速、工作温度和工作电压对 NH ₃催化分解和 H ₂电化学氧化速率的影响，以及对 NH ₃转化率、H 原子利用率和电效率的影响管状 DA-SOFC。结果表明，通过匹配 NH 的速率可以实现高 H 原子利用率。₃分解与H ₂电化学氧化。观察到随着温度的降低，H ₂氧化的速度比NH ₃分解的速度降低得更快，这表明应该适当降低NH ₃的流速以优化H原子的利用。最后，我们建立了 H 原子利用率、工作电压和电效率之间的相关性，以协同优化工作条件。在0.7 V和800 ℃下，以27 mL·min ^-1 NH ₃为燃料的管状DA-SOFC能够提供3.2 W，显示效率为60%。与管状 H _{2 相比}-SOFC（效率只有51%），在同等电压和燃料利用率的基础上，效率明显更高。本研究的结果证明了管状 DA-SOFC 作为高效发电设备的潜力。