Iron air Battery a breakthrough in energy grids 2021

This is another day and another article about a potential revolutionary battery success. Even in the scientific community, everyone is excited about energy storage and our renewable energy mix is growing in the energy grid. We will always need new battery ideas to save energy. Welcome to Battery Decade.

So in our agenda in this article, there is an iron air battery which is also known as a rust battery.

Company Form Energy believes that saving energy as rust can be a breakthrough for our success in energy grids. So it plans to bring it to market on a large scale, not just for a wild research thesis or prime time. So let’s see what are the advantages and disadvantages of iron air batteries?

What is a Battery ?

A battery is a device that stores chemical energy and converts it into electrical energy. This is known as electrochemistry and the battery that underpins is called the electrochemical cell. One or more batteries can be made up of one or more (e.g. voltaic core piles) electrochemical cells. These electrochemical cells have two electrodes separated by an electrolyte.

So how does an electrochemical cell generate its electricity? To answer this question we need to know what electricity is. Simply put, electrical energy is a type of energy produced by the flow of electrons. In an electrochemical cell, electrons are produced by a chemical reaction that occurs at one electrode and then they flow to another electrode. This time electricity flows in the opposite direction of the flow of electrons in this electrochemical cell. Know more about batteries here.

Types of battery cells

There are two types of battery cells.

  • The first one is the Primary sales or non-rechargeable batteries.[e.g. Alkaline batteries (zinc manganese oxide, carbon); Aluminium-air battery; Atomic battery; Bunsen cell; Citric acid cell (Poggendorff cell); Clark Cell]
  • The second one is the Secondary sales or rechargeable batteries.[Aluminium-ion battery; Calcium battery; Lead-acid battery;Glass battery;Lithium-ion battery,Iron air battery ]

In this article, we are talking about iron air batteries. So let’s check this out…

What are Iron air batteries made of?

Iron air battery is just one example of metal-air batteries. Each works in the same way. They have an anode on one side. In this case, there is a small pebble-shaped iron shell. On the other side is an air-breathing cathode. The whole thing is then immersed in a water-based non-combustible electrolyte solution. Not too different from what you might find in a standard double battery.

How does a iron air battery work?

Oxygen flows from the atmosphere to the cell where it reacts with iron through electrolytes. This reaction reduces the air to hydroxide and the iron first oxidizes to iron hydroxide. Where it releases electrons then turns into iron oxide.

iron air battery
image source: form energy website

As the battery removes those electrons, rust accumulates on the cathode. To recharge the battery you need an electric current to pass through the cell which actually reverses the process we talked about. Releasing oxygen again and rusting back to the iron.

It is this process of rusting and unrusting the iron that allows the battery to charge and discharge electricity. So it turns out that rust is not always a bad thing and that means an iron air battery is a rechargeable battery or a secondary cell. Compared to primary cells like aluminum air batteries which are not rechargeable.


Even when applied to grid-level storage iron air batteries have the advantage of long discharge. About 100 hours or more according to form strength.

Okay, I need to give it a little time and a little clarity. I am starting to see such claims very often and they can be a bit misleading.

Suppose we have a theoretical battery that runs on 10 volts and has a capacity of 100 MPh. Voltage bar amps give us about one thousand watt-hour or one-kilowatt hour battery.
The charge and discharge speed of a battery is usually measured in C where 1C means you can draw current up to 100 amps at filling capacity. At this rate, you will reduce the battery in one hour. Two C’S in two hours and 30 minutes or half C.

Iron-air Battery vs Lithium-ion

So iron air batteries cannot discharge as fast as lithium batteries. While this is not exactly an advantage it is true with a C rating of .001 but it will take one hundred hours to drain the battery.

But to be fair you can get even less current out of a lithium ion battery. The C rate is a maximum that you can pull without damaging the battery. But any small amount of current is also fine. It’s like trying to empty a bathtub. If you want to do it fast, you’ve got a large diameter hose that looks like a higher C quality in our batteries.

About the Company Form Energy

Okay now let’s see what we can find out. One company that is quietly refining this technology is Form Energy. The company’s CEO, Matteo Jaramillo, is a former Tesla employee with experience running Tesla grid energy storage. Tesla must have effectively started the grid energy game in 2017 with the classic subtle move to create the world’s largest battery in South Australia.

form energy iron air batteries
image source: form energy website

while working at tesla Jaramillo recognized that as incredible and groundbreaking as EV technology is. the technology can only do so much if recharging them still requires burning fossil fuels. this observation inspired him to look at past battery technology both successes and failures.

To see if he could find a more promising approach. he decided not to pursue lithium-ion batteries for grid storage like tesla is currently doing. As great as lithium-ion batteries are they have a few challenges. one challenge is flammable electrolytes. which are dangerous and can cause thermal runaway events. which is just an engineer’s way of saying they can catch on fire or explode. 


also with EVs and grid storage demand for lithium is going to go exponential in comparison iron is far more abundant at over 50 000 parts per million.

now my personal view has always been to save all the lithium and other rarer materials for our more weight-intensive applications like the millions of EVs and airplanes will soon be manufacturing.

which is why many of the grid storage applications use a special formulation of lithium-ion called lithium iron phosphate. which ditches the nickel manganese and cobalt in favor of iron. though they do still need some lithium.

  in the four years since then, the company has made some major strides and overcome some serious roadblocks that have previously kept iron air batteries from truly taking off. now according to Haramio the batteries a company is developing could be a major game-changer .possibly even displacing fossil fuels entirely in only a matter of years. so how exactly do they plan to do this?

Pros and cons

one major wind performs iron air batteries are the materials. simple easy abundant just air which is literally everywhere and iron which has a number of benefits over other battery materials. that doesn’t mean it’s inherently better than lithium across the board or that we shouldn’t use lithium for other applications. iron for instance is less energy-dense resulting in EVs with less range for the same weight . but by diversifying the materials we use and spreading them out over different technologies we can create a more sustainable energy ecosystem, which is not the whole point .

iron and other materials could help cool some of the geopolitical pressure building around lithium-ion supply chains .while opening new doors to different energy technologies to truly thrive. using more abundant and accessible materials could also have a major impact on cost. cost is maybe one of the most critical factors to consider when it comes to energy storage.

coal was once king until natural gas came along .cutting coal’s share of the energy price in half of the last two decades. but if we really want to create a clean sustainable future we need an energy storage solution that can meet demand without driving up cost.
the materials used in existing lithium-ion batteries cobalt nickel manganese and of course lithium translate to roughly 50 to 80 dollars per kilowatt-hour .form energy says that swapping these materials for iron could bring down the cost to below one-tenth of that.


just six dollars per kilowatt-hour or possibly even less. even a fully packaged battery system would top out at around 20 dollars per kilowatt-hour . this could represent a major tipping point in the green energy storage game. but let’s talk turkey, how do iron batteries stack up against lithium-ion batteries and other battery technology in terms of energy density .

form energy says that its large batteries use a giant iron anode and the company says that it’s the biggest anode ever made. the cells which are about a meter square are slotted into battery modules around the size of a washing machine. and can be rolled out in mass and installations. according to form their least dense configuration would get about one-megawatt hour of capacity into about an acre of land . with their higher density configurations reaching about three-megawatt hours in the same space.

for comparison my tesla power wall is 13 kilowatts of capacity and i’d need 77 of them to store one megawatt hour of electricity. but i could easily fit 77 power walls in my garage compared to a one acre complex for the iron air battery .this is why nothing in engineering is ever easy. we trade safety environmentally sustainable materials and cost for a much larger footprint .covering acres of our planet with batteries has an environmental cost all its own. but because of the safety of iron air batteries i’m optimistic that form energy is working on multi-level buildings and other optimizations to drive the land usage down .

but with all these comparisons to lithium-ion it deserves to be said that even according to form energy ceo the idea is not to supersede or replace lithium-ion but to complement it possibly even designing systems where the two technologies are paired together.

lithium-ion batteries could be the peaker plants that can quickly provide huge amounts of electricity when there are sudden surges in the grid.  and batteries like iron air can provide steady baseline power at night stored from renewable sources like solar during the day. 

for those familiar with the ebbs and flows of battery technology you may be asking yourself two things.the First one what’s the catch and the second one  iron air batteries aren’t new if they’re so great then how come no one else has rolled one out already.

for the first question it’s true .

iron air batteries first hit the scene during the 1970s and looked to be a promising contender for evs and energy storage during the oil crisis. back then however the technology suffered from a serious and seemingly insurmountable roadblock. basically during recharge a process called hydrolysis drained away about 50 percent of the battery’s energy.


however in 2012 USC researchers were finally able to jump the hydrolysis hurdle when they discovered that by adding a small amount of bismuth sulfide into the battery. they could reduce the waste 10-fold. form energy has basically perfected the process in laboratory conditions and has plans to build a large scale megawatt level prototype capable of discharging for more than six days by the end of 2023.

form energy has some secret sauce here some intellectual property that gives them a market advantage in overcoming this critical challenge. just how well it works and how reliable the resulting battery proves to be still remains to be seen.  form energy will have to offer good warranties to appease those wary of the unproven technology .those of you that follow the battery industry closely know many technologies have been seemingly stuck in this validation process.

stuff like solid state batteries that are always seemingly just a few years away. the challenge here with all batteries is in making a truly reversible process . cycle after cycle without degradation .no battery we will ever design will be perfect or last forever. but a form can create a large affordable grid scale battery that can last for decades not years.  i think they’ll have a very promising future. already the company has attracted investors like bill gates and jeff bezos. as the company develops over the next few years we may finally start seeing some major shifts in renewable energy storage.

but what do you think are you hopeful for iron air batteries and companies like Form energy or are you skeptical that this is all just another overhyped promise that will ultimately lead nowhere. let us know in the comment section below .so that does it at our look at the rust battery i love that name thinking about rust as a way of storing energy it’s pretty fascinating .


iron air batteries are rechargeable and while they’re not very energy dense they’re cheap and affordable .aluminum air battery aren’t rechargeable but they’re crazy energy dense.

so this is the age of the battery i think the next 10 years will be all about batteries and we will cover as much of that stuff as we can when we hear more about it.

So thank you to all of you for reading this article. Check out more information like this on Technifox.

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