Schiffer Zachary J, Biswas Sayandeep, Manthiram Karthish
Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125, United States.
ACS Energy Lett. 2022 Oct 14;7(10):3260-3267. doi: 10.1021/acsenergylett.2c01826. Epub 2022 Sep 6.
While solid and liquid energy carriers are advantageous due to their high energy density, many do not meet the efficiency requirements to outperform hydrogen. In this work, we investigate ammonium formate as an energy carrier. It can be produced economically via a simple reaction of ammonia and formic acid, and it is safe to transport and store because it is solid under ambient conditions. We demonstrate an electrochemical cell that decomposes ammonium formate at 105 °C, where it is an ionic liquid. Here, hydrogen evolves at the cathode and formate oxidizes at the anode, both with ca. 100% Faradaic efficiency. Under the operating conditions, ammonia evaporates before it can oxidize; a second, modular device such as an ammonia fuel cell or combustion engine is necessary for complete oxidation. Overall, this system represents an alternative class of electrochemical fuel ionic liquids where the electrolyte is majority fuel, and it results in a modular release of hydrogen with potentially zero net-carbon emissions.
虽然固体和液体能量载体因其高能量密度而具有优势，但许多载体不符合优于氢气的效率要求。在这项工作中，我们研究了甲酸铵作为一种能量载体。它可以通过氨和甲酸的简单反应经济地生产，并且在环境条件下为固体，便于运输和储存。我们展示了一种电化学电池，该电池在105°C下分解甲酸铵，此时甲酸铵为离子液体。在此，氢气在阴极析出，甲酸根在阳极氧化，两者的法拉第效率均约为100%。在操作条件下，氨在氧化之前就会蒸发；需要第二个模块化装置，如氨燃料电池或内燃机，才能实现完全氧化。总体而言，该系统代表了一类另类的电化学燃料离子液体，其中电解质主要是燃料，并且能够以模块化方式释放氢气，潜在实现净碳排放为零。
