Ammonia borane as an efficient direct fuel in alkaline fuel cells: mechanism, catalysts, applications, and challenges

Abstract

Ammonia borane (NH₃BH₃, AB) has attracted attention as a carbon-free energy source owing to its non-toxicity, high solubility in water, and high stability under ambient conditions. Unlike its traditional application as an efficient hydrogen storage material, AB has the potential to be used in alkaline fuel cells directly as an anode fuel. The direct ammonia borane fuel cell (DABFC) with a high equilibrium voltage of 1.616 V possesses high capacity and energy density with a value of 5200 A h kg⁻¹ and 8400 W h kg⁻¹, respectively. The AB oxidation reaction (ABOR) as the anodic reaction of the DABFC is the key to improving the electrochemical performance of the whole fuel cell. Up to now, there has been no report summarizing the direct application of AB as a fuel. In this mini-review, the mechanism, catalysts, applications, and challenges of AB applied as a fuel are discussed.