Researchers from the United States have made a critical discovery that has the potential to make sodium-ion batteries significantly safer and cheaper compared to lithium-ion batteries.
We already know EVs’ big dent in the transportation industry worldwide. However, these vehicles still need lower-cost batteries to power cars for higher ranges. At the same time, the world also anticipates low-cost batteries that can store the intermittent clean energy from wind and solar technologies to power hundreds of thousands of households.
And to meet these requirements, researchers worldwide are trying to create batteries beyond the current norm of lithium-ion materials. One of the most encouraging contenders is sodium-ion batteries.
Sodium-ion batteries are particularly appealing because of:
- Its greater abundance and lower cost (than lithium).
- An increased amount of stored energy when cycled at high voltage.
But, its performance also declined at a rapid pace with charge-discharged cycling, which hampered its commercialization.
Remarkably, researchers at the US DOE, Department of Energy’s Argonne National Laboratory have found a key reason for sodium-ion batteries’ performance degradation (1, 2). It is because of defects in the atomic structure that develop during the steps involved in the cathode material preparation.
These defects eventually cause a structural earthquake in the cathode, which leads to a catastrophic performance drop during the battery cycling.
Since battery developers have this knowledge, they can now adjust synthesis conditions to fabricate better sodium-ion cathodes.
According to the research team, their discovery was because of their reliance on the available user facilities and scientific capabilities at Argonne’s Center for Nanoscale Materials (CNM) and Advanced Photon Source (APS).
“We could track changes in the cathode material’s atomic structure in real-time with these capabilities while being synthesized,” said Guiliang Xu, an assistant chemist at Argonne’s Chemical Sciences and Engineering division (3).
Material fabricators slowly heat the cathode combination to a very high temperature in the air during cathode synthesis, keep it there for a specific period, then rapidly cool it to room temperature.
“Seeing is believing,” Yuzi Liu, a nanoscientist at CNM, stated (4). “We don’t have to guess what’s happening during the synthesis because of Argonne’s world-class scientific facilities.” The scientists used the transmission electron microscope at CNM, and synchrotron X-ray beams at the APS to accomplish this (at beamlines 11-ID-C and 20-BM).
According to their findings, the cathode particle surface became less smooth and exhibited extensive areas of strain when the temperature was rapidly dropped during material production. The research also revealed that a push-pull force occurs in certain locations during cathode cycling, resulting in cathode particle breaking and performance degradation.
The team discovered that this degradation was accelerated when cycling cathodes at high temperatures (130 degrees Fahrenheit) or charging them quickly (one hour instead of 10 hours).
An Argonne Distinguished Fellow, Khalil Amine (5), stated, “Our discoveries are tremendously significant for the large-scale manufacture of better sodium-ion cathodes. Considering the vast amount of material involved, say 1000 kg, there will be a huge temperature variation, resulting in many flaws appearing unless appropriate precautions are followed,” says the author.
Earlier team members’ research had produced a vastly improved anode. “Now we should be able to compare our enhanced cathode with the anode to get a 20%–40% performance gain,” Xu said (6). “What’s more, with long-term cycling at high voltage, such batteries will keep that performance.”
The impact could lead to an extended driving range in more cheap electric vehicles and lower energy storage costs on the grid.
The research was published in Nature Communications in a paper titled, “Native lattice strain-induced structural earthquake in sodium layered oxide cathodes.” Are you interested in reading the entire article? Here’s the link.
Nevertheless, with plans in the works, Tesla might be one of the first electric vehicle manufacturers to use sodium-ion batteries if their performance improves. Because sodium-ion batteries are created using the same method as lithium batteries, they may be available sooner and at a lower price than other options.
Sodium-ion Batteries are Booming
In September 2021, CATL, Contemporary Amperex Technology Co., Ltd., a major battery supplier to Tesla, Volkswagen, and other automakers, announced that a sodium-ion battery production line would be operational by next year. Meng Xiangfeng, CATL’s assistant to the chairman, spoke about the company’s ambitions at an industrial conference in China focusing on carbon neutrality (7).
The Chinese battery manufacturer holds 32% of the global EV battery market.
According to Xiangfeng, CATL has finally overcome several technical issues related to the production of sodium-ion batteries, including raw material production constraints. The task now is to expand production capacity and establish a raw material supply network (8).
As the automotive sector converts to electrification, sodium-ion batteries may become a feasible solution. According to the company, CATL’s first-generation sodium-ion batteries feature a high energy density, fast charging capability, outstanding thermal stability, and exceptional low-temperature performance.
The new sodium-ion battery tech could lead to the broad adoption of EVs by lowering costs and making electric vehicles cheaper. Furthermore, sodium-ion batteries lack the key metals used in nickel-cobalt-aluminum (NCA), nickel-cobalt-manganese (NCM), and lithium iron phosphate (LFP) batteries: lithium, cobalt, and nickel.
Lithium Vs Sodium-ion Batteries
The natural abundance of affordable sodium as a raw material is likely the most significant advantage of sodium-ion batteries. It is inexpensive to extract large amounts of it from saltwater.
According to the most recent data from Bloomberg New Energy Finance (BNEF), which follows the battery industry, the accessibility of cost-efficient sodium could make commercial production of sodium-ion batteries much less expensive than lithium-ion batteries, which currently cost around $126 per kWh to produce.
Although CATL did not reveal costs per kWh for producing its new sodium-ion batteries, the company claimed that its sodium-ion battery had an energy density of 160Wh/kg, which is currently the highest energy density for this type of battery in the world. The battery may be charged to 80% of its capacity in 15 minutes at normal temperature.
In addition, CATL’s sodium-ion batteries have a lower energy density than lithium-ion batteries, which have an overall energy density of 250-270 Wh/kg. However, CATL believes their next-generation sodium-ion battery’s energy density will transcend 200Wh/kg in the future as progress is made.
The performance in cold conditions is even better. The capacity retention rate of the sodium-ion battery is greater than 90% at -20°C, according to CATL. A conventional lithium-ion battery would normally lose roughly 40% of its available capacity at this temperature, resulting in a 60% retention rate.
CATL also recently announced its AB battery system solution, allowing users to mix and match sodium-ion and lithium-ion batteries to create a single battery pack. With battery management system (BMS) software, the two types of battery cells can be managed separately.
CATL’s AB battery software, for example, can adjust for sodium-ion batteries’ poorer energy density while utilizing the increased power and performance of modern lithium-ion or silicon-ion batteries in extremely cold temperatures.
CATL also wants to grow its collaboration with Tesla quickly and become the company’s largest battery supplier internationally. In June, a senior source at the Chinese company told Reuters that it aims to supply half of the battery cells Tesla uses for its EVs and energy storage systems.
CATL had announced in 2020 that it was ready to produce an electric vehicle battery that would last 1.2 million miles or 16 years before it needed to be replaced (9).
Batteries are the New Oil
Reliance Industries, led by India’s richest man Mukesh Ambani recently acquired a UK-based startup Faradion focused on sodium-ion batteries, for 136 million USD to compete with CATL (10).
The recent deal is Reliance’s sixth acquisition in the renewable energy industry. It was part of a $10 billion strategy to produce and fully integrate all “critical elements of the New Energy ecosystem,” including solar panels, batteries, electrolyzers, and fuel cells at every stage of the supply chain.
The proposal aims for the conglomerate, covering everything from textiles and polyester fibers to petrochemicals and petroleum refining, to develop six gigafactories in India by 2024.
According to Faradion CEO James Quinn, the company plans to develop a double-digit gigawatt fab for its Na-ion manufacturing ambitions (11).
“It’s evident that Reliance is fully committed to sodium-ion technology and is establishing gigafactories. And this is what the technology requires to scale: to make 1GW of cells, you need roughly 2,500 tonnes cathodes, so the size to get up to 10GW or 20GW is tremendous.”
With sodium-ion batteries emerging as a viable alternative to Li-ion batteries, both Reliance and CATL seems to be bent on bringing this technology into mass production from labs.
“Sodium-ion technology is still in its infant stages, but it might be a viable alternative to Li-ion technology, depending on how far firms are willing to invest,” says Max Reid, a Wood Mackenzie research analyst (11). Innovative battery technologies that use less or no crucial raw materials could help Li-ion supply chains cope with the growing demand.
Sodium is a thousand times more massive than lithium and has a virtually limitless supply, with significantly lower extraction and purifying costs. Na-ion cells are said to be 20 percent to 40 percent cheaper, but putting the technology to mass is a hurdle.
In addition, when it comes to production volume, Li-ion has already had a decades-long head start, lowering costs as it grew.
However, Quinn believes that by bringing Reliance and Faradion together under one roof, they would be able to keep innovating and progressing the technology while also expanding it at a vast scale.
“Their own captive need is so large,” Quinn argues, “that it can drastically reduce costs.” Reliance Industries, which controls the world’s largest telecom firm with 450 million users and operates 22,000 trucks, might have tens of gigawatts of captive demand.
Furthermore, by 2030, the company intends to create at least 100GW of solar installations, which it may choose to pair with batteries. Quinn says, “I believe it is the best opportunity for sodium-ion to become popular truly.”
Faradion claims to have achieved a significant increase in energy density by cumulative, iterative improvements to its cathode, anode, and electrolyte, demonstrating a capacity of 190Wh/kg that is now being put into production.
Quinn acknowledged that the team operates on step-change technologies and hopes to boost the energy density to 250Wh/kg. That would put it on par with most Li-ion batteries on the market today.
In their next generation of sodium-ion batteries, both Reliance and CATL aim for more than 200Wh/kg energy density. The cost of manufacturing sodium-ion batteries is often 20% to 40% lower, which may improve their appeal.
At the same time, as the cost of raw materials rises, some experts anticipate the date when electric vehicles will be competitive with gas cars will be pushed back to 2026 (12). Hence, with sodium-ion batteries gaining traction, they may soon offer a less expensive alternative to lithium in electric passenger vehicles.
“Sodium-ion batteries are manufactured using the same procedures and equipment as lithium-ion batteries. As a result, the infrastructure already exists, and no extra capital expenditure is required,” said Ruth Sayers, operations and technology director at Faradion (13).
“Tesla’s decision to utilize LFP has truly opened up the sodium battery chemistry. It’s primarily an LFP replacement technology, so sodium-ion can go everywhere LFP goes.”
Sodium batteries are substantially less expensive, potentially saving up to 40% on material expenses. They don’t include lithium, which requires hundreds of liters of water to extract from rock or brine for each tonne produced, or cobalt, tied to human rights violations and environmental degradation in the Democratic Republic of Congo. The present collectors on both electrodes are made of aluminum rather than copper.
The earliest uses of Faradion are in the three-wheeler sector. Reliance New Energy Solar, the company’s new owner, would employ its technology in India in its expected Gigafactory. Also, Faradion is discussing joint ventures with truck and bus companies.
Producers of sodium-ion batteries can benefit from “thirty-odd years of expertise making lithium-ion batteries. You can leverage a lot of that knowledge to enhance sodium-ion (technology) very quickly,” suggests Dustin Bauer, a patent attorney at Reddie & Grose (14).
However, CATL does not believe sodium will supplant lithium. “Unlike lithium-ion batteries, sodium-ion batteries have distinct advantages and may be tailored to various applications. Sodium-ion and lithium-ion batteries will coexist and complement each other in the long run.”
Na-ion will eventually be seen as a complement to Li-ion rather than a competitor. The two battery technologies are very similar in terms of composition and functioning principles, and they can commonly share assembly lines and equipment. As a result, CATL is simply merging its sodium-ion product into its current Li-ion infrastructure and ecosystem.
“We’ve launched our AB battery system solution, which combines sodium and lithium-based cells in a single EV pack, allowing us to use the benefits of both chemistries while also expanding the possible applications for sodium-lithium battery systems,” a CATL spokesperson stated.
The system makes up for the present energy density shortfall of sodium-ion batteries and takes advantage of their low-temperature performance.
The Closing Remark
Batteries may well be the new oil, but will they bring the same environmental damage?
Batteries may well be the new oil, but will they bring the same environmental damage? We can reduce the carbon footprint of batteries if we find ways to remove considerable quantities of critical elements. China’s recycling capacity is rapidly expanding, while startups worldwide have the chance to integrate recycling from the outset.
Several initiatives to create recycling systems are underway in the United Kingdom.
Several initiatives to create recycling systems are underway in the United Kingdom. Johnson Matthey has partnered with European Metal Recycling to establish a fully closed loop method for lithium-ion batteries and cell manufacturing components. At the same time, Faradion plans to cover the entire battery lifecycle as the company grows.
“The technique for recovering sodium is identical to the mechanism for recycling lithium-ion batteries. In some ways, it’s easier because you don’t have to segregate the materials in the same manner, and you only have aluminum rather than aluminum plus copper,” Sayers explained.
Faradion is also working on a ‘green cell,’ in which the components are compostable.
Another newcomer, Britishvolt, teamed up with mining and recycling giant Glencore in early February, first to process lithium-ion trash from its gigafactory, which is set to start mass production in early 2024. In addition to recycling, it also intends to reduce the amount of carbon incorporated in the battery cells it makes.
At the Knowledge Transfer Network, a battery technology conference, Dr. Allan Patterson, the company’s chief technical officer, said (15) that the company wants to produce no more than 25kg of carbon dioxide per kWh of production. In the United States and Europe, the benchmark is around 60 kilograms per kWh, but in China (which is highly reliant on coal power), it is around 90 kilograms per kWh.
“The big stages are to localize cathode material manufacturing, do it with renewable energy, and possibly do it for the graphite system as well,” says the researcher. Britishvolt also aims to “advance the cell’s performance.”
“Hence, it is crucial if you can increase the energy density. But it also comes down to [the] primary active elements and how they are manufactured, as well as how they are recycled.”