Sulfur is an attractive material for energy storage because it is abundant, inexpensive, and can store more energy than materials used in batteries today. Still, sulfur-based batteries have not reached their full potential. The various forms sulfur takes during operations are not well understood. This project focuses on a newly discovered liquid sulfur phase. This liquid form of sulfur has not been explored even though it may be a transformative energy material. The project will investigate how different sulfur phases form, transform, and interact with electrodes during charging and discharging. The team will design sulfur-based electrochemical cells that deliver high energy density quickly and efficiently. The project will lead to a better understanding of sulfur phases and pave the way for low-cost, high-performance sulfur-based energy storage systems. The project will establish a Microscopy, Spectroscopy, and Electrochemical Characterizations (MSEC) program for OU students and the local automotive industry. This project will provide undergraduate research opportunities in the Engineering Chemistry program, introduce K–12 students and teachers to energy science and engineering concepts, and inspire the next generation of scientists and engineers. Sulfur is a highly promising cathode material due to its abundance, low cost, and exceptionally high theoretical capacity. However, the behavior of sulfur during battery operations — especially its phases and transitions, which govern electrochemical performance — is poorly understood. This project highlights a liquid sulfur phase at room temperature, a newly discovered, largely unexplored, and potentially transformative energy material system. The project comprises four objectives: (1) Understand intermediate sulfur phases using in situ and operando platforms; (2) Chemically generate liquid sulfur on carbon electrodes using redox mediators; (3) Electrochemically generate liquid sulfur on carbon electrodes via fast a