Potential electrolyte additives for hydrogen economy: Screening of amino-based ionic liquids through COSMO-RS

Abstract. The identification of hydrogen as a prospective energy source for the substitution of non-renewable energy sources such as fossil fuels and natural gas has been acknowledged. Nevertheless, the existing methodologies used in the production of hydrogen exhibit significant drawbacks, mostly focused on the substantial release of greenhouse gas (GHG) emissions linked to the process. One potential approach to produce environmentally friendly hydrogen is alkaline water electrolysis, whereby potassium hydroxide (KOH) is used as the electrolyte. However, alkaline water electrolyzers, which use potassium hydroxide (KOH) as an electrolyte, have significant technological challenges in their performance. Commonly used ionic liquids as an electrolyte additive in this process are non-biodegradable. Previously amino-based ionic liquids had not been used as an electrolyte additive. Therefore, it is necessary to explore some biocompatible ionic liquids to be used as an electrolyte additive. Amino-based ionic liquids include a class of chemicals that exhibit biocompatibility and provide the possibility of customization, making them a promising option for improving electrolyte properties. This study will use the Cosmo-RS quantum methodology to evaluate amino-based ionic liquids with favorable physicochemical characteristics. The anions, cations, and water structures were created using TURBOMOLE version 21.0.0 (TmoleX) and the triple valance polarised basis set (TZVP) program package. Choline glycine and Choline Serine were found to have high ionic conductivity of 0.9578 mS/cm and 0.6945 mS/cm respectively. It was also observed that proline, glycine, serine, and asparagine anions can interact with water molecules better as compared to other anions as they show high peaks in non-polar regions.