Batteries are one of the key technologies for flexible energy systems in the future. In particular, vanadium redox flow batteries (VRFB) are well suited to provide modular and scalable energy storage due to favorable characteristics such as long cycle life, easy scale-up, and good recyclability. However, there is a lack of detailed original studies on the potential environmental impacts of their production and operation. The present study fills this gap by providing a comprehensive life cycle assessment of a representative VRFB. Transparent and comprehensive inventory data are disclosed as a basis for further environmental studies. VRFBs are found to be promising regarding the assessed impact categories, especially at high energy-to-power (E/P) ratios. On the other hand, significant impacts are associated with the vanadium pentoxide production, which is why the origin and processing of the vanadium bearing ores are a key for further reducing the environmental impacts associated with the VRFB manufacturing. While the lower efficiency of the VRFB is a disadvantage in comparison to e.g. lithium-ion batteries (LIB), its recyclability is significantly higher. In this sense, the importance of taking a cradle-to-cradle life cycle perspective when comparing very different battery systems can be highlighted for further research on this topic.