Flow-based energy conversion and storage technologies, such as redox flow batteries, flowable supercapacitors, and fuel cells, are considered prominent candidates for grid energy storage to support the electrification of transportation, integration of the renewables, and improvement of grid reliability and efficiency. Flow systems also show much promise for water treatment, including seawater desalination and wastewater remediation. However, these technologies present unique challenges in materials development, ranging from electrolyte solution thermodynamics, electrode surface catalytic functionality, to membrane polymer chemistry and morphology. Materials properties of the electrolyte, electrode, and membrane are critical to the performance. On the other hand, recent developments of hybrid flow systems, such as the lithium-ion flow battery, solar rechargeable flow battery, and photocatalytic fuel cell, etc., have demonstrated the importance of the synergistic effect between flow-based electrochemical device and other energy technologies. Current advancements in flow battery and fuel cell science and technology have positioned them for transformational performance improvement. However, the continuing success in this field is hinged upon the new materials development with improved functionality and properties.This symposium will provide a forum to discuss the advanced materials and challenges for flow-based energy conversion and storage technologies, as well as their applications and economic effectiveness as both stationary and transportation energy systems.