Safer, Cheaper, and More Powerful? The Promise of Aluminum Batteries

High-capacity batteries that charge faster and last longer are key to powering the future of portable electronics, electric vehicles, and long-term energy storage.

For the past few decades, lithium-ion batteries have been leading this sphere. A type of rechargeable battery, lithium-ion batteries are charged and discharged by the movement of these ions between the positive electrodes and negative electrodes, i.e., anodes and cathodes.

The metal lithium used in these batteries is soft, silvery, and highly reactive. It has the lowest density of all metals and is found in compounds as a mineral, with Chile being its biggest producer. Chile also has the largest lithium reserves, followed by Australia and China; the latter is also a leader in lithium-ion batteries.

These batteries actually require huge amounts of water and energy to produce. They are also very difficult to recycle.

So, while lithium-ion batteries have proven their performance in portable consumer electronics like smartphones, laptops, and other handheld devices, as well as EVs and storage systems for solar power backup, the market is now searching for materials that can outperform lithium-ion and power the next-generation of devices, long-range vehicles, electric aircraft, and grid-level storage.

This has led researchers to aluminum, which shows promising performance for safer, cheaper, and more powerful batteries.

Aluminium’s Potential in Advancing Batteries 

Efforts to develop rechargeable aluminum batteries have been going on for many decades now but gained significant traction in the past decade or so. Increased attention and research have helped Al-ion batteries achieve exceptional rates in charging and discharging. 

All the developments surrounding Al-ion batteries are significant due to the superior benefits this electropositive metal brings to the table. 

Aluminum’s unique properties include being lightweight, corrosion-resistant, and having high thermal conductivity. 

This versatility has made this metal highly beneficial in a wide range of applications in various industries, notably transportation. Metal is used extensively in the manufacturing of automobiles, airplanes, and trains because it is lightweight and strong, which helps improve fuel efficiency and reduce emissions. 

Another major application of aluminum is in the construction industry because it is easy to work with and has the ability to withstand harsh environmental conditions. Aluminum is also heavily used in packaging, aerospace, chemical, military, and electrical industry.

Having a low density and being a good conductor of electricity makes aluminum ideal for the manufacturing of electrical conductors, devices like computers, smartphones, and televisions, and usage in overhead power lines.

More importantly, aluminum is the most abundant metal element found in the Earth’s crust. Being a low-cost metal, its usage in rechargeable batteries can substantially reduce the cost of batteries, especially for economical, large-scale backup systems for renewable energy storage. 

Lithium-ion batteries are still too expensive for these applications. Besides being costly, these batteries also carry a flammable electrolyte that creates a safety concern. The most abundant metal on Earth and second most abundant metal commercially (after iron) makes for a suitable alternative here.

In addition to being cheap, aluminum also has a high volumetric capacity, which is four times larger than that of lithium and seven times greater than sodium. This showcases aluminum’s potential to enhance the energy density of batteries on a per-unit volume basis.

Moreover, aluminum is noninflammable, which further supports its adoption as an electrode. The use of this metal also removes the complexity from an interphase layer that is commonly seen in lithium-ion systems. 

That’s not to say that aluminum is without any deficiencies. The passivation, corrosion, and hydrogen evolution of aluminum ion battery systems have led to their limited application. Another challenge for aluminum ion batteries is the selection of anode materials due to the high charge density of Al3+ ions, which results in sluggish diffusion kinetics, in turn limiting the rate capability of the battery. 

Despite these challenges, aluminum-ion batteries are a promising candidate for large-scale energy storage due to their high specific capacity, low cost, lightweight, good safety, and aluminum’s natural abundance.

Exploring Aluminum-Ion Battery for Real-world Use

The exploration of aluminum in batteries has been going on for some time due to the need for new battery chemistries to fulfill the demand for high energy by the likes of aircraft to fly long distances and utility-scale storage of energy. Conventional batteries simply do not hold enough energy to power these systems.

It was about a decade ago that researchers at Stanford University revealed for the first time that an aluminum-ion battery can be stable and cycle for a long time. This Al-ion battery could be fully charged within one minute and go through up to 7500 charge/discharge cycles with little capacity decay.

A study conducted by researchers at the University of Queensland, Australia, late last year meanwhile addressed the technical hurdle with an AIB component¹ called the solid-electrolyte interphase.

An Al-ion battery, much like lithium-ion batteries, has an anode, a cathode, and an electrolyte, which carries aluminum ions that flow between the positively-charged electrodes and the negatively-charged electrodes. 

During discharge, the ions move from the anode to the cathode to generate energy, and when charging the battery, the process reverses to store energy. When it comes to Al-ion batteries, they face instabilities when cycling between charging and discharging due to the formation of dendrites that cause short circuits, which leads to battery failure.

The answer to this, as per the research, was that aluminium-ion batteries need pre-cycling, much like lithium-ion batteries, to maximize their lifetime. Understanding these unique pre-cycling needs can lead to better designs that enable a battery to last longer and perform more reliably, hence bringing them closer to real-world applications.

In yet another research from a couple of years ago, researchers from the Georgia Institute of Technology used aluminum foil to create batteries that could enable EVs to cover longer distances on a single charge.

In this study, researchers added small amounts of over 100 different materials to aluminum to create foils with specific “microstructures.” The aluminum anode was able to store more lithium than traditional anode materials, which means more energy, leading to the creation of high-energy density batteries.

These researches into aluminum batteries hold immense potential in opening the door to more powerful battery technologies to power the future.

New Design to Extend Aluminum Batteries’ Life

Given the many benefits of aluminum-ion batteries, most recently, a new study published² in ACS Central Science took to designing a cost-effective and environment-friendly Al-ion battery that can help support the shift to sustainable, clean energy.

With the global push toward sustainability, the study noted the need to explore abundant and renewable resources for advancements in energy storage battery technologies to foster sustainable development.

So, the researchers turned to rechargeable aluminum-ion batteries (AIBs) with nonflammable room-temperature chloroaluminate-based ionic liquid electrolytes. Their wide temperature adaptability, long cycle life, and exceptional safety make AIBs highly suitable for systems capable of storing energy on a large scale. 

But, of course, traditional ionic liquid electrolytes in AIBs suffer from notable vulnerabilities. With their new framework, researchers aim to overcome the problem of corrosion from the most common electrolyte used in Al-ion batteries. 

The electrolyte — liquid aluminum chloride — not only corrodes the aluminum anode but exacerbates this condition due to its high sensitivity to moisture. This contributes to poor stability, resulting in a decline in electrical performance over time. 

To remove this limitation, researchers introduced an inert aluminum fluoride salt to the electrolyte that contained an Al-ion, which turned it into a solid-state electrolyte. The 3D porous structure of the aluminum fluoride salt allows aluminum ions to easily hop across the electrolyte and increase conductivity. 

The researchers also used fluoroethylene carbonate as an interface additive. A thin solid coating of this on the electrodes helped prevent the formation of aluminum crystals and, in turn, protected the health of the battery from deteriorating.

With these two components, the team was able to enhance the moisture resistance of their battery along with its thermal and physical stability. This allowed the solid-state Al-ion battery to withstand temperatures up to 392 degrees Fahrenheit (or 200 degrees Celsius). It also stood firm against repeated jabs from a sharp object.

When it comes to the life of this battery, the study found it to be exceptionally long. The solid-state Aluminum-ion battery lasted as many as 10,000 cycles of charge and discharge while experiencing a loss of fewer than one percent of its original capacity. 

What’s more, most of the aluminum fluoride used can be recovered with a simple wash. The AlF3 can then be recycled into another battery with only slightly diminished performance, further reducing the production costs of the battery.

“This new Al-ion battery design shows the potential for a long-lasting, cost-effective, and high-safety energy storage system. The ability to recover and recycle key materials makes the technology more sustainable.”

– Wei Wang, State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, China

The new battery increases the practicality of Al-ion batteries by reducing their manufacturing cost and extending their life, but further improvements are still needed in energy density, electrolyte stability, and life cycle for this battery’s commercialization.

Click here to learn about a study that debunked battery aging myths.

Major Players in the Battery Market

The emergence of promising next-generation battery technologies offers significant improvements in terms of energy density, safety, cost, and lifespan over current lithium-ion batteries. And they are anticipated to transform the energy requirements, driven by innovations that address the limitations of current technologies. 

So, now let’s take a look at companies that are pushing the boundaries of battery technology and can see huge growth in the coming years.

1. QuantumScape (QS -2.24%)

While the world is exploring alternatives, lithium-based batteries continue to be in the lead for now. Against that backdrop, QuantumScape Corporation is among the leading battery companies that develop solid-state lithium-metal battery technology for EVs and other applications. 

With legacy lithium-ion batteries approaching their limit, the company has developed what it calls the first anode-free cell design of the industry to deliver high energy density, reduced material costs, and simplified production. 

Unlike conventional lithium-ion batteries that have a polymer separator, QuantumScape uses a solid-state separator. This enables the replacement of carbon or silicon anode with a lithium-metal anode, which is more energy-dense and hence stores a greater amount of energy in the same volume. In QuantumScape’s design, the battery is manufactured anode-free and in a discharged state.

As per QuantumScape, its 24-layer A0 prototype cell has completed over 1,000 full charge-discharge cycle equivalents with over 95% energy retention. Back in Oct., the company unveiled its planned first commercial product, QSE-5, for automotive applications. The QSE-5 B-sample cell, whose low-volume production has begun, has a measured cell energy of 21.6 Watts-hours (Wh). The QSE-5 cells can charge from 10% to 80% in a matter of about 12 minutes.

With a market cap of 2.62 billion, QuantumScape shares are currently trading at $5.13, down 1.16% YTD. Its EPS (TTM) is -0.95, and the P/E (TTM) ratio is -5.38.

For the last reported quarter’s financial results, i.e., Q3 2024, the company had $17.9 million in capital expenditures while its GAAP operating expenses came in at $130.2 million and GAAP net loss was $119.7 million. Liquidity at the end of the quarter was $841 million.

QuantumScape also partnered with Volkswagen’s battery manufacturer PowerCo to bring its QSE-5 tech to mass production.

During this period, the company reported successfully implementing its new separator production technology called the Raptor. Then, in December, the company announced the release of Cobra, which QuantumScape says will put it on track to deliver higher-volume samples of QSE-5 this year. Cobra is also regarded as a major step toward the commercialization of its solid-state batteries for EVs.

2. Solid Power (SLDP -4.36%)

Founded in 2011, Solid Power was spun out from the University of Colorado Boulder with funding from DARPA. Over the years, it secured contracts from the Air Force and signed an agreement with the Department of Energy.

In 2018, the company had its first round of equity-based financing, and in 2021, it announced a $135 million investment round led by the BMW Group, Ford Motor Company, and Volta Energy Technologies. 

Both Ford and the BMW Group have since expanded their existing joint development agreements with Solid Power to secure all solid-state batteries for their future EVs. In the year prior to that, Solid Power had produced 320 Wh/kg 20Ah lithium metal cells that it reported to be outperforming commercially available lithium-ion specific energy.

The company is involved in the development of next-gen all-solid-state battery technology, which it says has the potential to revolutionize future mobile power markets. Its focus is particularly on sulfide-based solid electrolytes for EVs, with a cost target of $85/kWh. The goal is to scale electrolyte production to power 800,000 EVs using its battery cells annually by 2028.

With a market cap of 268.77 million, Solid Power shares are currently trading at $1.50, down 21.16% YTD. The company only began trading on the Nasdaq in late Dec. 2021. Its EPS (TTM) is -0.47, and the P/E (TTM) ratio is -3.14.

For its most recently reported financial results, Q3 2024, Solid Power delivered $4.7 million in revenue, which was a decrease of $1.7 million from the same quarter the previous year. This drop in revenue came primarily due to the completion of its milestones with BMW. Its operating expenses for the period came in higher due to increased production costs, development cost of cell and electrolyte, operation scaling, and executions. Its liquidity position, however, remained strong as SolidPower ended the quarter with $348.1 million in total liquidity.

During this period, the company began working in its electrolyte innovation center (EIC) to improve the manufacturing processes of its pre-pilot electrolyte.

Most recently, Solid Power announced that it has secured as much as $50 million in funding from the U.S. Department of Energy for continuous production of sulfide-based solid electrolyte materials. As part of an Assistance Agreement, Solid Power will contribute $60 million of its own funds to support equipment installation, which is expected to bolster the company’s manufacturing scale.

Conclusion 

Lithium-ion batteries continue to reign supreme in many common consumer electronics, electric vehicles, and energy storage systems (ESSs). The growing adoption of these batteries is due to their high energy density and mature industrial preparation systems, but if we want to integrate abundant and renewable energy sources into the power grid, we need to find better solutions.

The long-term storage of solar and wind power requires large batteries, but Li-ion batteries are cost-prohibitive for this task. Not to mention, their flammability poses a considerable safety risk. A potential substitute for reliable, large-scale energy storage systems is rechargeable Al-ion batteries, which present a promising alternative with their lower cost, improved safety, and high volumetric capacity. 

With advancements in electrolyte stability and battery life, aluminum-ion batteries could play a key role in large-scale energy storage, EVs, and beyond. While challenges remain in their commercial viability, ongoing research is bringing these batteries closer to real-world applications and may soon be serving the future societal need for high energy density and affordable batteries.

Click here for a list of top battery stocks to invest in.