Development of a High-Performance Ammonium Formate Fuel Cell

Direct formate fuel cells are attractive due to their high theoretical voltage of 1.45 V, facile and complete formate oxidation in alkaline media, and ease of handling during storage and transportation. However, the presence of cations in the fuel solution only increases the weight load of the fuel cell system without contributing to electricity generation. In this work, an ammonium formate fuel cell is developed, which can not only retain the advantages of formate but also substitute the Na⁺/K⁺ with ammonium (NH₄⁺) to release electrons for electricity generation. This fuel cell achieves a peak power density of 61 mW cm^–2 at 60 °C. By replacing pure oxygen with hydrogen peroxide and increasing the temperature and fuel concentration, the peak power density is increased to 337 mW cm^–2. In addition, a mathematical model incorporating mass/charge transport and electrochemical reactions is developed to illustrate the voltage losses.