Guidance Introduction Flow batteries (FBs) are a versatile electric energy storage solution offering significant potential in the energy transition from fossil to renewable energy in order to reduce greenhouse gas emissions and to achieve sustainable development goals. The vanadium flow battery (VFB) is the most common installed FB.
Flow batteries were first proposed in the early 1880s and have since undergone many developments 11. Figure 1a illustrates the general configuration of conventional RFBs and basic working principles. RFBs work in a distinctly different fashion to Li-ion batteries.
Flow-battery technologies open a new age of large-scale electrical energy-storage systems. This Review highlights the latest innovative materials and their technical feasibility for next-generation flow batteries.
The cost and operating system management of various active redox species for the flow batteries are clearly illustrated in Table 2.More importantly, it can be estimated that the cost of Fe/Cr active material is $9.4 kWh 1, which makes ICRFB the most likely to match the cost expectation of RFBs by the US Department of Energy.
The iron-chromium redox flow battery (ICRFB) is considered the first true RFB and utilizes low-cost, abundant iron and chromium chlorides as redox-active materials, making it one of the most cost-effective energy storage systems.
To overcome these disadvantages, a growing effort has been focused on developing novel systems to increase energy density and operating voltage. This trend, which has been referred to as the ‘renaissance of the flow batteries’ (Ref. 6), is very similar to the interest in fuel-cell technologies in the early 2000s.