(674d) Ammonium Formate As a Safe, Energy-Dense Electrochemical Fuel Ionic Liquid
AIChE Annual Meeting
2021
2021 Annual Meeting
Innovations in Process Engineering
Materials and Processes for Thermo-, Electro- and Photo-Chemical Energy Storage
Monday, November 15, 2021 - 1:45pm to 2:10pm
In this work, we propose ammonium formate, a combination of ammonia and formic acid, as an energy carrier. Not only is its production as cheap and simple as its constituent molecules, ammonium formate is a benign solid at ambient conditions, making it safe to transport and store. We demonstrate an electrochemical cell that takes advantage of the fact that ammonium formate forms an intrinsically conductive ionic liquid at 116â; as an ionic liquid, ammonium formate has negligible vapor pressure and is significantly safer than either ammonia or formic acid alone. In this system, hydrogen is evolved at the cathode with near 100% Faradaic efficiency and formate is oxidized to carbon dioxide at the anode with near 100% Faradaic efficiency. In theory, ammonia could be oxidized to nitrogen in the same cell, however we observe that the operating temperature makes it so that ammonia gas evaporates from the cell and can be oxidized using a second, modular ammonia fuel cell. Because molten ammonium formate is conductive, the electrolyte and feed can approach 100% ammonium formate fuel, resulting in a large thermodynamic driving force. Overall, this system represents a new class of electrochemical fuel ionic liquids and results in modular release of H2 with the potential for zero net carbon emissions.