Redox flow batteries: Status and perspective towards sustainable stationary energy storage

Redox-flow batteries, based on their particular ability to decouple power and energy, stand as prime candidates for cost-effective stationary storage, particularly in the case of long discharges and long storage times. Integration of renewables and subsequent need for energy storage is promoting effort on the development of mature and emerging redox-flow technologies. This review aims at providing a critical analysis of redox-flow technologies that can potentially fulfill cost requirements and enable large scale storage, mainly aqueous based systems. A comprehensive overview of the status of those technologies, including advantages and weaknesses, is presented. Compiled data on the market permeability, performance and cost should serve, together with the perspective included, to understand the different strategies to reach the successful implementation, from component development to innovative designs.European Union under HIGREEW, Affordable High-performance Green Redox Flow batteries (Grant Agreement no. 875613) and CuBER, Copper-Based Flow Batteries for energy storage renewables integration (Grant agreement no: 875605) projects. Basque Government (GV-ELKARTEK-2020 KK-2020/00078), Spanish MINECO (RTI2018-099228-A-I00 and RYC2018-026086-I (Ramon y Cajal fellowship) E.V.) and CDTI (Centro para el Desarrollo Tecnológico Industrial, CER-20191006) are also acknowledged for funding this work. R.M. thanks the European Research Council (ERC) through “MFreeB” project (grant agreement no. 726217