(General Student Poster Award Winner - 1st Place) Six Practices to Improve Alkaline Electrolyte Preparation

Abstract

Alkaline electrolytes represent a critical component of electrochemical energy devices, including alkaline electrolyzers, fuel cells, supercapacitors, and alkaline batteries. In addition, these electrolytes define essential properties of electrocatalytic reactions, such as the oxygen evolution reaction (OER), the hydrogen evolution reaction (HER), and the oxygen reduction reaction (ORR). However, alkaline electrolyte concentrations and compositions are often considered trivial, resulting in misinterpretation of different phenomena and overestimating critical performance metrics. Thus, in an expanding field full of interdisciplinary research groups, there is an urgent need for standardized protocols designed to improve and evaluate the quality of alkaline electrolytes so that electrochemical energy systems can be objectively examined and compared.In this work, we propose a protocol composed of six steps to prepare, characterize and validate the quality of common alkaline electrolytes. By adapting well-established methods in the literature and validating additional features experimentally, we standardize six general practices: (1) proper alkaline electrolyte handling and preparation, (2) removal of Fe impurities, (3) alkali molarity standardization via pH titrations, (4) electrolyte composition analysis via inductively-coupled plasma mass spectrometry (ICP-MS), (5) statistical quality control assessment and (6) electrolyte validation through electrochemical aging of Ni electrodes in alkaline media. The effects of Fe incorporation for different alkaline electrolytes were examined using Ni and NiFe foam electrodes. Furthermore, ICP-MS measurements were complemented with prolonged cyclic voltammetry tests to confirm the effectiveness of the Fe purification procedure. We believe this work illustrates the importance of standardizing protocols and reporting reliable quality metrics to improve consistency and accuracy in electrochemistry. Furthermore, adopting the practices presented in this work would greatly benefit the evaluation and comparison of electrochemical energy materials and devices operating with alkaline electrolytes. Figure 1