Cobalt-Free Batteries Could Power the Next Generation of Electric Vehicles

  

Vinod Kumar
Published : April 8, 2024

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Many of today’s electric vehicles rely on powerful lithium-ion batteries containing cobalt, a metal that comes with high financial, environmental, and ethical costs. However, researchers at MIT’s Department of Chemistry may have found a more sustainable solution to power the electric cars of the future – a cobalt-free battery design.

This innovative new battery ditches cobalt and nickel for a cathode made from organic compounds. In a recent study released in January 2024, the MIT team demonstrated that this organic cathode material can conduct electricity at rates similar to conventional cobalt-based batteries. Remarkably, their cobalt-free battery also matched the energy storage capacity of cobalt-based versions while allowing for even faster charging times.

Read along as we discuss more about this innovation and its impact on the future of the automobile industry.

What Are Cobalt-Free Batteries?

Cobalt has been a critical element in traditional lithium-ion battery cathodes, such as lithium cobalt oxide (LCO) and nickel-cobalt-aluminum (NCA) cathodes, due to its high energy density and relative stability. However, the issues surrounding cobalt mining and production have prompted researchers and manufacturers to explore alternative cathode materials that eliminate or minimize the use of cobalt.

One such alternative is the Lithium Iron Phosphate (LFP) batteries: These batteries use lithium iron phosphate as the cathode material, which is free of cobalt and relatively abundant. LFP batteries are known for their safety, long cycle life, and thermal stability, but they have a lower energy density compared to cobalt-based batteries.

Challenges of Cobalt in Lithium-Ion Batteries

The use of cobalt in lithium-ion batteries, which power most electric vehicles (EVs) and rechargeable electronics, presents several significant challenges, including:

Limited Availability

Over two-thirds of the global cobalt supply comes from the Democratic Republic of the Congo (DRC). This geographic concentration of mining creates risks around access and pricing instability. As demand for cobalt rises with increased EV production, costs could fluctuate dramatically.

Environmental Impact

Cobalt mining, especially in the DRC, has been linked to environmental damage and human rights violations. The practices at many cobalt mines are rightly criticized as unethical and unsustainable. Reducing cobalt dependency is important to mitigate these issues.

Cost

While cobalt improves battery performance, it also increases costs substantially compared to cobalt-free alternatives. With cobalt demand and prices expected to rise, finding lower-cost cathode materials is imperative for affordable EVs. Also, the researchers at MIT highlight that “as you transition to a much higher proportion of electrified vehicles in the consumer market, it’s certainly going to get more expensive” if cobalt remains a key battery ingredient.

Social and Human Rights Issues

Cobalt mining, particularly in the DRC, has been associated with reports of child labor, unsafe working conditions, and other human rights violations. These unethical practices not only exploit workers but also contribute to the mistreatment of vulnerable populations. Continued reliance on cobalt could exacerbate these issues and perpetuate the cycle of exploitation in the mining industry.

Alternatives to Cobalt Batteries

Cobalt is a scarce metal with prices that can fluctuate dramatically. Moreover, much of the world’s cobalt supply comes from mines in politically unstable regions where extraction creates hazardous working conditions and toxic environmental contamination.

Also, because of cobalt’s economic, environmental, and ethical issues, researchers have sought alternative battery materials that can match cobalt’s performance without the heavy baggage. One option gaining traction is lithium-iron-phosphate (LFP), which some automakers have begun using in electric vehicles. However, LFP has only about half the energy density of cobalt-based batteries.

Organic materials represent another promising alternative to cobalt. Most organic candidates investigated so far have struggled to achieve the conductivity, storage capacity, and cycle life of cobalt-containing batteries. Their low conductivity often requires mixing in polymer binders, which dilutes the battery’s energy density.

Now, researchers at MIT may have found a breakthrough organic material for cobalt-free battery cathodes. The team, led by Professor Mircea Dincă, developed a layered structure made from an organic small molecule called bis-tetraamino benzoquinone (TAQ). This fully organic cathode material demonstrates high conductivity on par with cobalt-based cathodes.

The key is TAQ’s molecular structure containing quinones that can accept electrons and amines that form strong hydrogen bonds. This allows the layers to assemble into a stable, graphite-like structure that is insoluble in the battery’s electrolyte. Dincă’s team showed their TAQ cathode could cycle over 2,000 times with minimal degradation from material dissolution.

If this organic, cobalt-free battery can be commercialized, it could eliminate the problematic supply chains, price volatility, and environmental hazards associated with cobalt mining. Dincă’s cobalt alternative points toward more sustainable energy storage for powering the electric vehicles of the future.

How Can Cobalt-Free Batteries Power Cars of the Future?

The transition to electric vehicles is a key part of reducing greenhouse gas emissions from transportation. However, the lithium-ion batteries used in most current EVs rely on cobalt, a rare metal with limited supplies that is often mined under unethical conditions. Researchers are therefore seeking alternatives that avoid cobalt entirely.

The TAQ material is composed of abundant elements like carbon, nitrogen, and hydrogen that are inexpensive and easily sourced compared to cobalt.

Despite being cobalt-free, batteries with the TAQ cathode matched or even exceeded the performance of conventional cobalt-containing batteries in key metrics:

• Energy storage capacity comparable to cobalt batteries
• Faster charging rates than cobalt batteries
• Excellent cycle life of over 2,000 charge/discharge cycles with minimal degradation

The organic TAQ cathode material is also more environmentally sustainable than cobalt mining. It is based on precursor compounds that are already produced commercially in large volumes. Estimates show the materials cost could be one-third that of cobalt batteries.

By avoiding cobalt and rare metals entirely, the TAQ battery tackles both the supply constraints and ethical issues around cobalt while providing the performance needed for powering electric vehicles. This cobalt-free organic battery chemistry represents a promising path toward more sustainable energy storage for the cars of the future.

Need for Materials Testing in Cobalt-Free Batteries

That being said, there are still several key challenges that must be addressed before these cobalt-free batteries can be commercialized for electric vehicles. One major hurdle is verifying that the new TAQ-based cathode material can meet the stringent performance, safety, and longevity requirements for automotive applications. As a result, extensive materials testing and validation will be required to ensure the cathode can withstand the demanding operating conditions of an electric vehicle over its full-service life.

Also, some critical areas that will require thorough evaluation include:

Mechanical Properties

The cathode’s mechanical integrity must be characterized through thousands of charge/discharge cycles to confirm it can withstand degradation from volumetric changes during operation. Techniques like electron microscopy can analyze the cathode structure after cycling.

Thermal Stability

The cathode’s behavior must be tested under the high temperatures that can occur in automotive battery packs during rapid charging or external heating events. Calorimetry and other thermal analyses can verify stability and safety.

Environmental Resilience

Automotive duty cycles involve frequent temperature swings and potential vibrational stresses. Accelerated environmental testing is needed to validate the cathode’s resilience to these conditions.

Chemical Compatibility

Chemical reactivity and electrolyte degradation behavior must be measured to qualify the cathode for integration with other battery components and ensure long calendar/cycle life. Large-scale prototyping on the multi-layer pouch or cylindrical cell formats will also be required to properly vet the cathode’s performance when scaled up from lab samples. Rigorous inspection and analytical testing at each stage gates release for the next phase of development.

Wrapping Up

This breakthrough in cobalt-free battery technology from researchers at the University of Texas at Austin could be truly transformative for electric vehicles and consumer electronics. By incorporating organic compounds like cellulose and rubber into the cathode, these new batteries maintain high energy storage capacity while solving challenges around cathode cracking and degradation.

The potential impact is substantial. Electric vehicles equipped with these cobalt-free batteries could see drastically reduced charging times, making them far more practical for consumers. With improved cathode integrity, these batteries may last significantly longer than current lithium-ion batteries, extending the lifespan of EVs and electronic devices.

Perhaps most promisingly, the researchers suggest this organic battery technology could make manufacturing batteries much cheaper than current production methods. If costs come down, it could catalyze broader adoption of affordable electric vehicles powered by this longer-lasting, fast-charging battery.

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