Demand for batteries is growing worldwide, driven by their increasing use in the automotive industry, the rising popularity of portable consumer electronics, and stringent environmental regulations. As a result, the global battery market has been projected to reach $800bln by 2036, up from about $120bln in 2023.
In light of this expected growth, researchers are continuously developing and testing new materials and chemicals to improve critical parts of batteries, which affect properties such as energy output, energy storage, power capacity, and cycling capacity.
These components include a cathode (positive electrode), an anode (negative electrode), an electrolyte (for ion transportation between electrodes), and a separator.
Most battery-powered devices today, such as EVs, smartphones, and energy storage systems, rely on lithium-ion battery technology. Lithium-ion batteries can store a huge amount of energy in compact sizes, charge fast, and last long.
However, with the growing demand for batteries with greater capabilities, new technologies are being researched and developed to improve efficiency, reduce cost, enhance safety, and promote sustainability.
Over the years, continuous research has led to advancements that offer promising alternatives to lithium-ion and lead-acid batteries.
Sodium-ion batteries offer a more affordable and safer option that performs better at lower temperatures. These batteries are similar to lithium-ion batteries but utilize saltwater as an electrolyte, making them more suitable for energy storage, though they are yet to be optimized. Researchers are even using electrolyte gel to make nanowires more resilient and fit for battery use.
Solid-state batteries, on the other hand, use a solid electrolyte such as glass, ceramic, or polymer instead of gel or liquid electrolyte. These batteries are far more efficient, weigh less, charge faster, and are already being used in smartphones and pacemakers. Toyota and BMW are currently working on launching solid-state battery-powered cars, though it will still take a few years.
New battery technologies further include lithium-sulfur batteries, which are cost-efficient but have a durability limitation, and cobalt-free lithium-ion batteries, which can help address human rights concerns in cobalt mining. However, alternatives like TAQ are still new and need more testing.
Zinc-based batteries are also being explored, with technologies including zinc-manganese dioxide, zinc-air, zinc-bromine, and zinc-ion batteries. However, they are inefficient, sometimes involve unexpected chemical conversion reactions, and are expensive to manufacture, requiring more research.
As the world increasingly relies on batteries, scientists globally are focused on achieving breakthroughs in storage times, power output, production costs, and instant readiness.
Latest Battery Breakthrough: Rock Salt-polyanion Cathodes
New research has made an advancement in increasing the practical energy density of the battery. Published in Nature Energy late last month, the study titled “Integrated rocksalt–polyanion cathodes with excess lithium and stabilized cycling,” was conducted by the MIT Department of Nuclear Science and Engineering.
The study focuses on a new cathode material found in disordered rock salt, which has been studied as an advanced cathode material for use in lithium-ion batteries for over a decade.
MIT researchers made sure that the material can create high-energy, low-cost storage for EVs, mobile phones, and renewable energy storage.
Led by Ju Li, the Tokyo Electric Power Company Professor in Nuclear Engineering, the team discovered DRXPS, or disordered rock salt-polyanionic spinel, as the new material.
This new category of partially disordered rock salt cathode, integrated with polyanions, is found to deliver high energy density at high voltages with enhanced cycling stability. This is a great achievement, given that there is typically a trade-off between energy density and cycling stability in cathode materials.
“With this work, we aim to push the envelope by designing new cathode chemistries.”
– Yimeng Huang, the paper’s first author, a postdoc at the NSE
Now, how is the new material family able to achieve both high energy density and good cycling stability? The answer lies in the integration of two key cathode materials — rock salt and polyanionic olivine. By combining them, it was able to get both of their benefits.
Another thing at play here is manganese (Mn), a hard, silvery metal found in abundance on Earth and much cheaper than other elements currently used in today’s cathodes.
For example, Manganese is about thirty times less expensive than Cobalt (Co) and five times less expensive than Nickel (Ni), both of which are commonly used in batteries. Additionally, Manganese plays a crucial role in achieving higher energy densities.
“(Having such a) material be much more earth-abundant is a tremendous advantage.”
– Li, a professor of materials science and engineering
This advantage, according to the researchers, is of great value to a zero-carbon future which requires renewable energy infrastructure.
Batteries can play an important role in this transition, with the potential to decarbonize transportation through electric vehicles and address the intermittency of solar and wind power. Since these renewable energy sources aren’t available 24/7, energy storage is essential for providing power during times when these sources aren’t available, such as at night or on overcast and calm days.
The researchers also point out that materials like cobalt and nickel are relatively rare and expensive. Using them to rapidly scale up electric storage capacity could lead to big spikes in costs and potentially significant shortages of materials. According to Li:
“If we want to have true electrification of energy generation, transportation, and more, we need earth-abundant batteries to store intermittent photovoltaic and wind power. I think this is one of the steps toward that dream.”
Overcoming the Hurdle of Oxygen Mobility in Current Materials
Funded by the Honda Research Institute USA Inc. and the Molecular Foundry at Lawrence Berkeley National Laboratory, the study tackled one of the major challenges disordered rock salt cathodes face.
As noted earlier, the material has been studied for its extremely high capacity. Compared to traditional cathode materials, which have a capacity between 190 and 200 milliampere-hours per gram, this material boasts as much as 350 milliampere-hours per gram.
However, despite offering very high capacity, the material isn’t very stable. This is partly due to oxygen redox, a process of harnessing electron density near oxygen atoms in cathode materials.
Oxygen redox is activated when the cathode is charged to high voltages, making oxygen mobile, which then leads to reactions with the electrolyte and material degradation. This renders the material useless after prolonged cycling.
To overcome these challenges, the researchers introduced another element into the material: phosphorus (P), a soft, waxy solid that acts like glue, holding the oxygen in place and reducing material degradation.
But just adding phosphorus is not enough in itself. It’s the right amount of phosphorus that is the most important innovation here. Adding just the appropriate amount of P “formed so-called polyanions with its neighboring oxygen atoms into a cation-deficient rock salt structure that can pin them down,” stated Li.
The strong covalent bonding between oxygen and phosphorus enables the researchers to put an end to the transport of oxygen. This way, they have been able to utilize the capacity contributed by oxygen and at the same time, achieve good stability.
Having this ability to charge batteries to higher voltages is important because it allows for simpler systems to manage their stored energy.
“You can say the quality of the energy is higher. The higher the voltage per cell, then the less you need to connect them in series in the battery pack, and the simpler the battery management system.”
– Li
This study is just the beginning, as the team will now explore different ratios of manganese, lithium, oxygen, and phosphorus, as well as various combinations of other polyanion-forming elements like silicon, sulfur, and boron.
Going forward, the researchers will also investigate novel ways to fabricate the material, with a particular focus on scalability and morphology. The current study uses high-energy ball milling for mechanochemical synthesis, which gives non-uniform morphology and particles the size of about 150 nanometers, a small average. Moreover, their current method isn’t really scalable.
So, the researchers are now trying alternate synthesis methods to achieve a more uniform morphology and particles with larger sizes. This would help increase the material’s volumetric energy density and may even allow them to try some coating methods that could improve the performance of the battery. Future methods must also be industrially scalable.
Another issue is conductivity, which was boosted by adding a significant amount of carbon to the disordered rock salt material. In fact, carbon made up 20 percent of the cathode paste’s weight, as the material isn’t really a good conductor by itself.
So, of course, researchers will further look into reducing the carbon content in the electrode. If they can achieve this without sacrificing the battery’s performance, they could increase practical energy density by incorporating a higher active material content into the battery.
To this end, they are considering using carbon nanotubes, which could reduce the carbon content to just one or two percent by weight, allowing for a significant increase in the active cathode material. The current study, however, used Super P, a conductive carbon composed of nanospheres, which is less efficient.
Another improvement involves using thick electrodes, which would further increase the battery’s practical energy density.
Once the team optimizes the material composition, develops thicker electrodes, achieves better morphology for uniform coatings, lowers the carbon content, and adopts scalable synthesis methods, they see the DRXPS cathode family as highly promising for applications in electric vehicles, grid storage, and consumer electronics.
Companies Advancing in the Field of Batteries
Many corporations are helping advance the field, and even more stand to benefit from these developments.
Umicore (UMICY) is one such company involved in battery materials, particularly in cathode technologies, with a focus on sustainable and advanced materials. Meanwhile, Lithium Americas Corp. (LAC is a lithium supplier, and Vale (VALE) is a leading global producer of iron and manganese. Now, let’s take a look at a few other prominent names:
#1. Albemarle Corporation (ALB)
A major lithium producer, Albemarle, has been developing battery technologies with increased energy density to reduce weight and extend range. It is one of the world’s largest producers of lithium for EV batteries. The company’s offerings to meet the demand for clean energy include cathode solutions, anode solutions, electrolyte solutions, and battery casings.
With a market cap of $9.84 billion, Albemarle’s stock is currently trading at $83.66, down 41.6% YTD. It has an EPS (TTM) of -4.73, a P/E (TTM) of -17.67, and a dividend yield of 1.94%. In Q2 of 2024, the company posted net sales of $1.4 bln and adjusted EBITDA of $386 mln. Cash from operations, meanwhile, was $363 mln, up from $289mln YoY. Albemarle also delivered over $150mln in productivity benefits.
#2. QuantumScape (QS)
QuantumScape is a developer of solid-state lithium-metal batteries, aiming to transform energy storage. The company has developed the industry’s first anode-less cell design, which lowers material costs and delivers high energy density. This year, QuantumScape partnered with Volkswagen’s battery company, PowerCo, granting them a license to mass-produce battery cells based on QuantumScape’s technology platform.
With a market cap of $2.75 billion, QuantumScape’s stock is currently trading at $5.51, down 19.78% YTD. It has an EPS (TTM) of -0.95 and a P/E (TTM) of -5.78. In Q2 2024, the company posted capital expenditures of $18.9 million, while GAAP operating expenses were $134.5 million. Liquidity stood at $938 million at the end of the quarter.
Conclusion
Given the wide usage and market size of batteries, new and advanced battery technologies are being heavily researched and developed. As we saw in the latest study, the new cathode material exhibited “high gravimetric energy densities above 1,100 Wh kg−1 and >70% retention over 100 cycles,” opening the door for battery cathodes made from earth-abundant elements like Mn and Fe.
Since lithium-ion batteries are seen as a crucial part of the clean energy transition, studies like this ensure their continued growth and price reduction by developing “inexpensive, high-performance cathode materials.”
This points to a promising future for energy storage, with the potential to meet growing global demands while minimizing environmental impact.
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