Ammonia-Fueled Tubular Solid Oxide Fuel Cell Using a Plasma-Enhanced Cracking Reactor

This study presents the first integration of an alternating current (AC) arc discharge plasma cracking reactor with a tubular ammonia-fueled solid oxide fuel cell (SOFC), significantly enhancing system stability and performance through pre-plasma treatment. It was discovered that ammonia conversion efficiency is co-regulated by the electrode gap distance, input power, and inlet gas flow rate: at low power (30 W), conversion increases with larger gaps; at medium-to-high power (50–90 W), conversion peaks at an 8 mm gap. For a fixed gap, conversion increases with higher power and decreases with higher flow rates, achieving 100% at 100 W and 50 mL min–1. Replacing pure ammonia with the plasma-cracked products at the anode boosts the maximum power density at 800 °C from 40.79 to 68.09 mW cm–2, representing a 60.4% enhancement. A 120 h constant-current test reveals stable cell voltage with fluctuations maintained within ±1.5% of the baseline without any degradation trend, demonstrating exceptional system stability. Mechanistic analysis indicates that plasma-driven decomposition of ammonia prior to entering the anode markedly alleviates the chemical-induced stress associated with in situ ammonia cracking within the anode, thereby extending cell longevity. This strategy provides an innovative approach for scaling up high-performance, long-lifetime ammonia-fueled SOFC systems.