Enhancing B/N-H Fuel Cell Durability: Insights from Degradation Mechanisms and Optimization

Abstract

This study investigates the critical durability challenges of direct liquid fuel cells using B/N-H-based fuels—decaborane (B₁₀H₁₄) and hydrazine borane (N₂H₄BH₃)—for practical applications. Operational tests reveal significant performance degradation in both direct decaborane fuel cells (DDFCs) and direct hydrazine borane fuel cells (DHBFCs). In DDFCs, a severe 81.6% loss of initial peak power density occurs within 1 h, mainly attributed to the structural instability of the anode catalyst layer and cathode catalyst poisoning. For DHBFCs, a 46.4% performance decline is observed in the same period, with the accumulation of electrochemical byproducts at both electrodes being the primary cause. To address these issues, various optimization strategies are used. For DDFCs, replacing the anode substrate, adjusting the ionomer/carbon ratio, and using a more poison-resistant cathode catalyst prove effective. In the case of DHBFCs, improving the anode gas diffusion layer and adopting AEMs significantly enhance performance. After optimization, DDFCs exhibit only a 6.7% performance degradation over 50 h of operation, while DHBFCs retain 95.7% of their initial performance. These findings provide crucial insights into the degradation mechanisms and optimization approaches for B/N-H-based fuel cell systems, facilitating their potential application in practical energy scenarios.