Iron based Flow Battery (IBFB) is a type of electrochemical energy storage technology that uses iron salt solution as the electrolyte and achieves energy storage and release through the redox reaction of iron ions.

The core principle is to use iron ions dissolved in the electrolyte as active substances, and complete the charging and discharging process through the circulation of positive and negative electrode electrolytes. Compared with other flow batteries such as vanadium flow batteries, iron-based flow batteries have the advantages of low raw material costs, abundant resources, and high safety.

For example, with abundant iron resources and a crustal content of about 5%, the cost of electrolyte is low, and the price of FeCl ₂ is about 1 yuan/kg. In addition, water-based electrolytes have no combustion risk and are suitable for large-scale energy storage scenarios. The theoretical number of cycles exceeds 10000, and in practical applications it can reach more than 5000 times without heavy metal pollution. The electrolyte can also be recycled.

At present, there are three main technological routes for iron-based flow batteries: all iron flow batteries, which use iron-based active materials for both positive and negative electrodes to avoid cross contamination; Iron chromium flow battery, with positive electrode Fe ³ ⁺/Fe ² ⁺ and negative electrode Cr ³ ⁺/Cr ² ⁺, but limited by the side reaction of Cr ² ⁺ hydrogen evolution; And zinc iron flow batteries, with positive electrode Fe (CN) ₆³ ⁻/Fe (CN) ₆⁴⁻ and negative electrode Zn ² ⁺/Zn, need to solve the problem of zinc dendrites.

But currently, the initial manufacturing cost of iron chromium flow batteries is relatively high, key materials such as proton exchange membranes rely on imports, and the energy density is lower than that of lithium batteries. But through large-scale production and localization of materials, costs are expected to significantly decrease.

In the field of zinc iron flow batteries, Weijing Energy Storage has built a 3GW zinc iron flow battery intelligent manufacturing base in Baotou, Inner Mongolia, which is expected to be put into operation in 2025. Zinc iron flow batteries use zinc as the negative electrode and iron as the positive electrode, with lower cost and higher safety, making them suitable for large-scale long-term energy storage.

2、 Expected to occupy 15% of the global energy storage market share by 2030

As a new large-scale energy storage technology, iron-based flow batteries are becoming one of the key technologies for global energy transformation due to their cost-effectiveness, long cycle life (theoretical over 10000 cycles), and environmental friendliness.

According to the report "Research on the Market Development Status and Investment Trends of China's Iron based Liquid Flow Battery Industry from 2025 to 2031", this technology has achieved an energy density increase of 15-35Wh/L by optimizing the electrolyte formula (such as FeCl ₂/FeCl3 system with a cost of only 1 yuan/kg) and battery stack design, while significantly reducing corrosiveness and maintenance costs.

Currently, the global iron-based flow battery market is dominated by North America (accounting for 44.98% in 2022), but China is accelerating its catch-up with its industrial chain advantages. The market size is expected to reach 12 billion yuan in 2025 and exceed 50 billion yuan in 2030, with a compound annual growth rate of over 30%.

In terms of technological breakthroughs, the Institute of Metals, Chinese Academy of Sciences has successfully achieved low-temperature operation at -20 ℃ and dendrite growth inhibition through electrode interface defect design and polar solvent adjustment, with a power density of 80mW/cm ². The 3GW zinc iron flow battery base built by Weijing Energy Storage in Baotou, Inner Mongolia is expected to be put into operation in 2025, reducing costs to below 1500 yuan/kWh.

The main participants include ESS company (iron chromium system), FormEnergy from the United States (long-term energy storage), Shanghai Electric (gigawatt level fuel cell), Dalian Rongke (demonstration project), and Kerun New Materials (localization of ion exchange membrane).

Despite facing cost competition from sodium ion batteries (expected to be 0.3 yuan/Wh by 2027), iron-based flow batteries still have irreplaceable potential in long-term energy storage scenarios such as grid peak shaving and renewable energy grid integration. Their market value will be further released with policy support and technological iteration (modular design, graphene composite film application), and they are expected to occupy 15% of the global energy storage market share by 2030.