Automated Determination of Concentration-Dependent Redox Properties for Redox Flow Battery Materials

The development of redox flow batteries (RFB), a promising answer for the energy storage challenges associated with intermittent renewable energy sources, hinges on a deep understanding of the complex physicochemical interactions among the solvent, electrolyte salt, and redox-active molecules within the RFB. To advance our understanding of these systems, we developed a robotic platform designed to automate the study of redox flow battery chemistry. This system integrates our ExpFlow software with a versatile modular robotic hardware infrastructure, allowing for precise, reproducible electrochemical experimentation. The electrochemistry platform automates the execution and analysis of cyclic voltammetry (CV) and chronoamperometry (CA) electrochemical procedures to quantify descriptors such as oxidation potential, diffusion coefficients, and conductivity. When validated with well-known electroactive systems, the system yields results that closely align with established literature values. We employed this automated system to analyze the effects of varying concentrations of the redox-active molecules (e.g., 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)) and electrolyte salts (e.g., TBAPF6) on solution diffusivity, conductivity, etc. The results demonstrate the platform's capability to enhance understanding of redox flow battery chemistry. While our system was conceived for redox flow battery research, its modular design and versatility enable application across a wide range of electrochemical studies.