Ammonium formate: Applications as Electrochemical Fuel Ionic Liquid and Safety

General Description

Ammonium formate is a promising electrochemical fuel ionic liquid, offering high energy density and efficient performance in energy conversion and storage applications. Ammonium formate's safe solid state allows for easy transportation and storage. However, concerns exist regarding Ammonium formate's safety in animal feed due to the presence of formamide. The FEEDAP Panel has raised issues about formamide's potential toxicity, especially for reproduction and non-food-producing animals. While reducing the maximum content in feed may address some safety concerns, further investigation is necessary, particularly for laying hens and sows. Consumer safety has been evaluated, with current levels not posing significant risks.

Figure 1. Ammonium formate

Applications as Electrochemical Fuel Ionic Liquid

Ammonium formate serves as a promising and safe electrochemical fuel ionic liquid, offering high energy density and efficient performance. This versatile compound is derived economically through a straightforward reaction between ammonia and formic acid. Furthermore, its solid state under standard atmospheric conditions ensures safe transportation and storage. In the realm of energy conversion and storage, ammonium formate exhibits its potential in an electrochemical cell operating at 105 °C, where it functions as an ionic liquid. Within this system, hydrogen evolution takes place at the cathode, while formate oxidation occurs at the anode, both achieving approximately 100% Faradaic efficiency. However, it is important to note that under these operational parameters, ammonia evaporates before complete oxidation can occur. Therefore, additional modular devices, such as an ammonia fuel cell or combustion engine, are essential for comprehensive oxidation. This innovative approach utilizing ammonium formate represents a distinct category of electrochemical fuel ionic liquids, distinguishing itself by having the majority of the electrolyte serving as the fuel. As a result, this setup facilitates a modular release of hydrogen, potentially leading to zero net-carbon emissions. The use of ammonium formate as an electrochemical fuel ionic liquid thus presents a promising alternative to traditional energy carriers, enabling efficient energy conversion while minimizing environmental impact. In summary, the application of ammonium formate as an electrochemical fuel ionic liquid holds great promise, offering an economically viable, safe, and efficient solution for energy storage and conversion needs. Its unique properties and functionality position it as a compelling candidate for sustainable energy solutions. ¹

Safety

Ammonium formate is a substance commonly used in animal feed, and its safety for all animal species has been a subject of scientific assessment. The European Commission requested the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) to provide a scientific opinion on the safety of this substance. In a previous opinion delivered in 2015, the FEEDAP Panel expressed concerns about the presence of formamide, a contaminant of ammonium formate, with regards to developmental toxicity for reproduction animals and carcinogenicity for non-food-producing animals. Additionally, the Panel highlighted potential consumer exposure to formamide through dairy animals and laying poultry, raising safety concerns. In response to these concerns, the applicant proposed a reduction in the maximum content of ammonium formate in feed, from 12,000 mg/kg to 2,000 mg formic acid equivalent/kg feed for pigs and other animal species. However, despite this proposal, the FEEDAP Panel was unable to conclusively affirm the safety of ammonium formate in complete feed for laying hens and sows. This determination was based on the calculation of the maximum safe concentration of formamide in feed, which exceeded the recommended levels for these specific species. Nevertheless, a residue study in eggs indicated that the use of ammonium formate in animal nutrition at a maximum content of 2,000 mg formic acid equivalent/kg complete feed would not pose safety concerns for consumers. In conclusion, while the reduction in the maximum content of ammonium formate in feed addresses some safety concerns, further investigation and consideration are needed, especially with regard to laying hens and sows. The potential impact on consumer safety has been evaluated, and at the proposed levels, the use of ammonium formate does not raise significant concerns. ²

Reference

1. Schiffer ZJ, Biswas S, Manthiram K. Ammonium Formate as a Safe, Energy-Dense Electrochemical Fuel Ionic Liquid. ACS Energy Lett. 2022; 7(10): 3260-3267.

2. EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP), Bampidis V, Azimonti G, et al. Safety of ammonium formate (E 295) for all animal species. EFSA J. 2020; 18(4): e06076.

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