Since a large scale energy storage system (ESS) stores electrical energy, it can solve various energy related problems such as macroscale black-out by load levelling at peak time without additional power plants. Also the ESS can be an effective approach to improve the reliability, power quality and economy of renewable energy. A vanadium redox flow battery (VRFB) is one of the most promising technology among the various ESSs because of non-explosiveness and scalability. In this study, the structural components of VRFB were investigated. The multifunctional components that have mechanical, chemical and electrical properties were developed with composite materials. The developed multifunctional composite structures improved the performance, reliability and economy of the VRFB system.