As the renewable energy sector continues to grow, so does our need for better and cheaper energy storage, which is why our reliance on lithium could become a bit of a problem. While there are already an assortment of energy storage options available today beyond lithium batteries for grid scale storage, like compressed air and pumped hydro, there’s still a search for the next big thing to satisfy our need in all the other use cases. One possible rising star is aluminum-based batteries, which don’t require rare-earth materials, can charge faster, and could be cheaper and easier to recycle. There are two exciting breakthroughs we must examine … and some of the benefits of these are kind of astounding. How do they work and can they really compete with lithium ion batteries? Let’s take a closer look.
So why do I talk about batteries so much on the channel? Well, our push towards more mobile electronic devices and vehicles, plus renewable energy sources is driving the need for a variety of cutting edge energy storage technology. According to the International Renewable Energy Agency, just renewable energy production alone will make up 85% of all energy produced worldwide. Solar and wind will make up 22% and 36% of that respectively.1 The problem is that these energy sources are intermittent and need energy storage to unlock their full potential.2
Over 90% of the world’s grid battery storage market is currently accounted for by Li-ion batteries, making them the most common type from portable electronics to grid-energy storage. The advantages of lithium-ion batteries include conversion efficiency, high power density, low self-discharge, and good service life. It’s pretty clear why they’re the reigning battery champ for not just the grid, but for everything from EVs to smartphones.3 4 5 6
However, it’s not all sunshine and rainbows for lithium-ion batteries. They have a relatively high cost, have flammability issues if they’re not managed properly, which leads to their need for power management to maintain safe operation. Lithium extraction isn’t exactly an environmentally friendly process right now, but companies like EnergyX are trying to solve that. And recycling has also been an issue, but that’s also getting solved by a bunch of leading recycling companies like Redwood Materials, Li-Cycle, and RecycLiCo. [^lithiumdrawbacks] 7 8 I’ve videos on all of those if you’re interested.
This is when the new contender for the battery crown enters the ring, but it feels like we have a new battery emerging almost every week, right? Here on this channel, we’ve covered several kinds of novel batteries that promise to overcome conventional battery issues. Some of those are just hitting the market now and others are still in the lab. These aluminum batteries overcome some of the same issues, and they really caught my eye because of the simplicity and availability of cheap materials combined with some crazy performance. So what is aluminum-ion all about?
Just as a quick refresher for how a battery works, the key components of a battery are the positive and negative electrodes, which are the cathode and anode. In between the electrodes is a separator made of a membrane or polymer, along with an electrolyte to help shuttle ions back and forth between the electrodes.9 10 11 12
Aluminum-ion batteries are conceptually similar to Li-ion batteries. There’s one clear difference between the two of them that gives aluminum the edge: it can exchange up to three electrons per ion, while lithium can only exchange one. That means that it takes three Li+ ions to equal one Al3+ ion.2 13 The higher number of electrons per Al3+ ion means a higher theoretical power density and capacity. There are challenges to that though, which we’ll get to in a bit, but that higher number of electrons per ion means a high theoretical volumetric capacity of 8,046 mAh cm-3, which is about 4 times greater than Li (2,062 mAh cm-3), and a gravimetric capacity of 2,980 mAh g-1, which is close to Li metal (3,860 mAh g-1) 13 14 On top of that, aluminum-ion is safer, potentially cheaper, and doesn’t have the same flammability concerns as lithium.2
Enough about theory, what about in the real world? The University of Queensland, for example, published their research on a graphene aluminum-ion battery in 2021.15 The Australian company, Graphene Manufacturing Group (GMG), has exclusive access to the University of Queensland technology to commercialize graphene aluminum-ion batteries. GMG is working towards producing commercial battery solutions for watches, phones, laptops, electric vehicles, and grid storage. 16 17
The innovative graphene aluminum-ion (G+Al) batteries operate in a similar way to conventional batteries. The technology uses aluminum and graphene rather than traditional graphite. GMG uses a plasma technique to manufacture graphene layers, which are so closely layered that the aluminum chloride atom that they’re using (about 5.5 nanometers in size) can’t fit between the carbon atoms (about 0.3 nanometers in between).15 16 17 18 They essentially drill tiny holes in the carbon layers (it happens through the manufacturing process) where the aluminum chloride atoms can sit.
All these structures and densely packed aluminum atoms make the G+Al battery achieve a charge rate up to 70 times faster than lithium-ion cells, according to the company. For example, a cell phone could be charged in minutes with these batteries. The limiting factor isn’t how much energy the battery can take, but the cable providing that power to the battery.
I had the chance to interview Craig Nicol, Founder and CEO of GMG, and he provided me with some details:
“Our battery is basically just carbon and aluminum, both extremely conductive and has a very low insignificant internal resistance. But when you take an internal resistance across the lithium battery, it’s actually quite a high internal resistance there.”
“Carbon is well-known for trapping heat as a little thing called global warming because of its ability to trap heat, and we see it has enormous ability to be able to trap and spin heat out.”
“We’ve tested this battery at already quite high temperatures, well above what lithium batteries can handle with no issue, so fast charging doesn’t seem to be an issue.” -Craig Nicol
Bottom line: graphene and aluminum are excellent at transferring heat out and away from the cell, which would reduce the need for complex cooling and battery management systems. The cells have decent performance too, with a power density equal to 150Wh/kg, but that’s much lower than what we typically see for lithium-ion at around 250 – 300Wh/kg.15 18 However, that aluminum-ion performance has shifted recently because these numbers have been increasing and can go ever higher:
“That was about a year ago when we first started. We announced that we had an energy density of about 150Wh/kg, and we announced earlier this week we’re now at 300Wh/kg. We’re only using one electron but it has the potential to go up by three times.” -Craig Nicol
Aluminum is a metal that’s far more abundant in the environment than lithium. In fact, it’s the most abundant metallic element in the earth’s crust, and the third most abundant element overall behind oxygen and silicon.19 This means that G+Al batteries won’t have scarcity problems like rare earth metals and lithium-ion batteries do. 18 Moreover, compared to lithium, aluminum is safer and more recyclable — it’s already one of the world’s most recycled metals. 20
“There’s a huge potential there of having a very low emissions based product. We aim to be a very low emissions producer of our battery in the first place. We’re trying to get as low emissions on our graphene production as possible. Obviously, refining aluminum from bauxite ore creates a lot of emissions, but it’s a 90% recycled material, and is significantly more efficient to recycle than process from virgin ore. And then we’re working with Rio Tinto to look to see how we can take their lower emissions aluminum or zero emissions aluminum and put those together. We’d have a very low emissions produced battery and it has thousands of cycles and at the end we can recycle it.” -Craig Nicol
The first G+Al battery pouch cells were produced in June 202221 and GMG also plans to build the first commercial facility for producing G+AI batteries, which are used to make coin cells. The business plans to start producing automobile pouch cells for the EV market by 2024.18
Of course, money talks in this industry. In battery cells, the cathode represents about 51% of total battery cost.22 In a typical lithium ion battery, the cathode is composed of lithium and other metals, such as cobalt, nickel and manganese. Comparing the metal prices, lithium costs around $13,000 per ton, while cobalt, nickel and manganese are currently priced at $71,000, $24,000 and $2,500 per ton. 23 24 Aluminum is much cheaper than those metals, costing around $2,078 per ton.18 Finding pricing data for graphene production is tough and varies wildly, but one report I found came out to about $100 per gram.25 However, that cost is dropping rapidly and it’s not clear how much it’s costing GMG to manufacture their specific blend.
So GMG is clearly at the pilot phase and starting to try and commercialize this aluminum-ion tech. Looking a little further out, because it’s still in the lab, there’s another piece of tech coming from research at MIT. They’ve developed an aluminum-sulfur battery that shows some very cool potential and published the research in the journal Nature. This battery was tested at 100 cycles at a high capacity of 520 mAh per gram, and has a high energy density of around 526 Wh/L. 26 27 28
Their tech is focused on using cheap and abundant elements, but it’s the electrolyte which is the most surprising. Aluminum and sulfur are used as the two electrode materials with a molten salt electrolyte. This electrolyte has several advantages, such as low melting point, the chloro-aluminate salt prevents dendrites and the occurrence of short-circuiting, as well as allowing for very fast charging. What’s really interesting is that the charging rate improves the hotter the battery gets. It can charge 25 times faster at around 110 degrees Celsius (230 F) versus 25 C (77 F). It’s also non-flammable, which reduces the risk of fire.29 28
It’s anticipated that this device could be used for small-scale stationary storage, automotive applications, and all the way up to powering homes and businesses. Regarding costs, MIT predicts that their aluminum-sulfur battery cell to be as low as $9 per kWh, which is about 12-16% of today’s lithium-ion battery cell cost. 26 27 Obviously, this still needs to get out of the lab, but it’s not a risky assumption to make that the cheaper cost of materials will have a big impact on final production cost.
Although the GMG and MIT batteries sound really promising, they share similar challenges. Perhaps one of the biggest challenges for aluminum-ion batteries practical application and commercialization is the Al reaction inside the battery. The metal can form alumina and dendrites and suffer corrosion, which can drop efficiency and safety. The self-corrosion should receive attention to facilitate the aluminum-ion practical applications because it can cause the irreversible consumption of the aluminum anode, which reduces the energy density and life span 30 The utilization of corrosion inhibitors, such as zinc oxide, and the development of alloys with magnesium, zinc, tin, indium, and gallium seems to reduce the self-corrosion rate.31
From an economic perspective, demand for aluminum-ion batteries has the potential to outpace other battery technologies in the future, primarily as a potential replacement for Li-ion batteries in the electric car sector. The global aluminum-ion battery market had a value of $4.2 billion in 2021. Taking into account all of the advantages, metal sources, and widespread use, the market is expected to reach $8 billion by 2031. 3233
As I pointed out in my previous solid state battery video, we have to find better battery technologies that can provide higher energy density, life span, safety, and cost to move away from fossil fuels and unlock the potential of our all electric future. So, will we ever see an aluminum-ion battery in the real world? It’s looking more likely by the day. GMG’s battery is an important step towards commercialization, but is still in the works. Aluminum-sulfur is still in the lab, but shows exciting possibilities. No matter what, it’s not about one technology killing another, but about finding the right tool for the right job. Having more options available to us like aluminum-ion is a good thing.
- Global energy transformation ↩
- Energy storage system ↩ ↩ ↩
- Energy Storage Today ↩
- What are some advantages of Li-ion batteries? ↩
- The lithium-ion battery ↩
- How Lithium-ion Batteries Work ↩
- Recent advances in rechargeable aluminum-ion batteries ↩
- Are lithium ion batteries recyclable? ↩
- How do Lithium Batteries Work? ↩
- Lithium-ion Battery charge and discharge ↩
- Lithium-ion batteries ↩
- Inside a Lithium-ion Battery Pack and Cell ↩
- Emerging rechargeable aqueous aluminum ion battery ↩ ↩
- Aluminium-ion Batteries ↩
- Ultra-fast charging in aluminum-ion batteries: electric double layers on active anode ↩ ↩ ↩
- GMG Aluminium-ion battery ↩ ↩
- Developer Of Aluminum-Ion Battery Claims It Charges 60 Times Faster Than Lithium-Ion ↩ ↩
- Introducing an Aluminum-Ion Battery that Charges 60 Times Faster than Lithium-Ion ↩ ↩ ↩ ↩ ↩
- Aluminum – Wikipedia ↩
- Aluminium recycling ↩
- GMG manufactures the first pouch cell ↩
- Breaking Down the Cost of an EV Battery Cell ↩
- Why manganese is a good investment? ↩
- Costs of nickel and cobalt used in electric vehicle batteries ↩
- Scientists found a way to make graphene 200 times cheaper and greener ↩
- A new concept for low-cost batteries ↩ ↩
- Aluminum-sulfur battery for small-scale storage ↩ ↩
- Aluminum Sulfur—Is This How the Future Spells Lithium Ion? ↩ ↩
- Cheap aluminium-sulfur alternative to lithium-ion batteries ↩
- Challenges and Strategies of Low-Cost Aluminum Anodes for High-Performance Al-Based Batteries ↩
- Corrosion behaviour improvement from the ultrafine-grained Al–Zn–In alloys in Al–air battery ↩
- Aluminium Ion Battery Market ↩
- Aluminum-ion Battery Market by 2031 ↩