The study explores the use of trapezoid channel design to enhance the volume power density in proton exchange membrane fuel cells that utilize ammonia decomposition gas, known as ammonia-hydrogen fuel cells. The presence of nitrogen at the anode in these cells typically leads to reduced power density. By implementing trapezoidal channels with varying upper edge lengths (0.1, 0.2, 0.4, 0.6), the research demonstrates a substantial increase in volume power density compared to traditional rectangular and triangular channels. The results show a remarkable enhancement, with power density improvements of 53.5%, 62.0%, 81.9%, and 108.3% when utilizing trapezoidal channels with the specified upper edge lengths. These values significantly outperform both rectangular and triangular channel configurations. However, it is noted that as the upper edge length of the trapezoidal channel increases, issues such as hydrogen hunger at the anode and cathode become evident. The study highlights that with longer trapezoidal channels, the fuel utilization efficiency may decrease, reaching levels as low as 76%. Overall, the research sheds light on the potential of trapezoid channel design to boost power density in ammonia-hydrogen fuel cells. While offering significant enhancements in power output, the study also underscores the importance of balancing design improvements with operational efficiency to maximize the benefits of this innovative approach.