How All-Iron Flow Batteries Work | EnergyLink
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How All-Iron Flow Batteries Work

How All-Iron Flow Batteries Work

All-iron flow batteries are a technology development that offer a potential long-lasting solution to safely, efficiently and cost-effectively storing renewable energy. Within the past decade this technology and its potential impact on grid-level energy storage has been extensively researched. Companies such as Energy Storage Systems and Electric Fuel ® have been devoted to the development and manufacturing of these batteries for commercial use.

What are All-iron Flow Batteries and How Do They Work?

Flow batteries are electrochemical cells that store energy in external tanks of liquid electrolyte that is pumped through electrodes to extract the electrons. When an energy source provides electrons, the flow pumps push the spent electrolyte back through the electrodes, recharging the electrolyte and returning it to the external holding tank. All-iron flow batteries use electrolytes made up of iron salts in ionized form to store electrical energy in the form of chemical energy. Storing chemical energy within an external battery container offers flow batteries flexibility to shift energy flow and rate of storage, which facilitates efficient energy management.

Using iron in flow batteries is particularly advantageous because it is earth-abundant and non-toxic and therefore creates an affordable and safe alternative for storing chemical energy. The ways in which all-iron flow batteries can benefit commercial businesses are outlined below. The benefits of all-iron flow batteries are outlined more extensively here.

Cost-efficient Technology

All-iron flow batteries have the longest lifespan and are one of the cheapest options compared to electrochemical energy storage devices such as supercapacitors, regenerative fuel cells with hydrogen storage, lead-acid batteries, lithium-ion batteries, sodium sulfur batteries and vanadium redox batteries. All-iron batteries last at least 15 years have a storage capacity cost that ranges from 250-400 $/kWh.

Lead-acid batteries are one of the only cheaper devices ranging from 400-600 $/kWh but will only last up to three or four years. Along with the drawback of a low lifetime, lead-acid batteries have a low energy density and are temperature sensitive. While all-iron flow batteries have their own drawbacks such as hydrogen evolution, low cell voltage and current efficiency, all of these can be overcome with suitable additives.

Environmentally Sustainable

Compared to zinc, vanadium or lithium-ion technologies, all-iron flow batteries are more environmentally friendly due to iron’s earth abundance. All-iron flow batteries offer a chemical energy storage solution to companies looking to reduce their environmental footprint.


All-iron flow batteries are a safer alternative to other metals frequently used in electrochemical energy storage devices, such as lithium. While lithium hydrates are toxic, flammable, react violently with water and corrode in air, iron is a relatively non-toxic alternative that is only slightly reactive with water and air. Because of this, all-iron flow batteries are a safer alternative especially in environmentally sensitive or fire-sensitive locations.


All-iron flow batteries are long-lasting and flexible. They offer commercial businesses the ability to efficiently manage energy by shifting energy flow and rate of storage to meet the organizations specific needs. All-iron flow batteries also do not require cooling requirements unlike other flow batteries, making installation and maintenance processes easier.

Interested in Flow Batteries?

EnergyLink can help you design, build, and fund your flow battery project today. Click the button below for a free quote or call our team at (866) 218-0380.

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