Advances in electrode and electrolyte improvements in vanadium redox flow batteries with a focus on the nanofluidic electrolyte approach

Vanadium redox flow batteries (VRFBs) are increasingly used in different large-scale stationary applications. In particular, this state-of-the-art energy storage system is used to deal with power management, peak shaving and load levelling and to support a large-scale renewable power grid. VRFBs offer many benefits such as long lifetime, flexibility, and relatively high performance; however, their high capital and operation costs has remained to be their major drawback compared to other more conventional energy storage systems (ESSs). Thus, significant efforts have been dedicated to modifying VRFB components in order to enhance their economic competitiveness while improving their performance. The present paper comprehensively reviews and discusses various electrode modification approaches, and electrolyte retainment techniques by focusing on their pros and cons and effects on the performance of VRFBs and the research gaps to be addressed. This paper also aims to explore another approach, known as the nanofluidic electrolyte technique , to simultaneously modify electrode and electrolyte. In addition, novel materials with different affecting properties suitable to be utilized in “nanofluidic electrolyte” technique for improving the performance of VRFBs are introduced and discussed.