CURRENT STATUS OF SODIUM-ION BATTERIES AND COULD THEY REPLACE LITHIUM-ION BATTERIES
vijay tharad
Director Operations at Corporate Professional Academy for Technical Training & Career Development
Sodium-ion batteries?(NIBs?or?SIBs) are several types of?rechargeable batteries which use?sodium ions?(Na+) as its?charge?carriers.
Sodium-ion battery development took place in the 1970s and early 1980s. However, by the 1990s, lithium-ion batteries had demonstrated more commercial promise, causing interest in sodium-ion batteries to decline.?In the early 2010s, sodium-ion batteries experienced a resurgence, driven largely by the increasing cost of lithium-ion battery raw materials.
ANODE:
Sodium ion batteries will have anodes from materials like Hard Carbon, Graphite, Tin, Molybdynum disulphide, graphene, Carbon arsenide.
Hard Carbon
SIBs can use?hard carbon, a disordered carbon material consisting of a non-graphitizable, non-crystalline and amorphous carbon. Hard carbon's ability to absorb sodium was discovered in 2000?This anode was shown to deliver 300 mAh/g. The first sodium-ion cell using hard carbon was demonstrated in 2003 and showed a 3.7 V average voltage during discharge.?Hard carbon is preferred due to its excellent combination of capacity, (lower) working potentials, and cycling stability.
Graphite
In 2015 researchers demonstrated that graphite could co-intercalate?sodium in ether-based electrolytes. Low capacities around 100 mAh/g were obtained. Further ?Na2Ti3O7?or NaTiO2,?delivered capacities around 90–180 mAh/g. though cycling stability was limited to a few hundred cycles. Numerous reports described anode materials storing sodium via alloy reaction and/or conversion reaction.?Alloying sodium metal brings the benefits of regulating sodium-ion transport and shielding the accumulation of electric field at the tip of sodium dendrites.
Tin
Sodium and metallic tin NaSn anode could operate at a high temperature of 90?°C (194?°F) in a carbonate electrolyte at 1 mA cm?2?with 1 mA h cm?2?and the full cell exhibited a steady cycling rate of 100 cycles at a current density of 2C.Despite sodium alloy's ability to operate at extreme temperatures and regulate dendritic growth, the severe stress-strain experienced on the material in the course of repeated storage cycles limits cycling stability, especially in large-format cells.
Molybdenum Disulfide
In 2021 researchers from China tried layered structure?MoS as a new type of anode for sodium-ion batteries. A dissolution-recrystallization process densely assembled carbon layer-coated MoS2?nanosheets onto the surface of?polyimide-derived N-doped?carbon nanotubes. This kind of C-MoS2/NCNTs anode can store 348?mAh/g at 2?A/g, with a cycling stability of 82% capacity after 400 cycles at 1?A/g.
Graphene
Graphene Janus particles have been used in experimental sodium-ion batteries to increase?energy density. One side provides interaction sites while the other provides inter-layer separation. Energy density reached 337 mAh/g.[22]
Carbon Arsenide
Carbon Arsenide(AsC5) mono/bilayer has been explored as an anode material due to high specific gravity (794/596mAh/g), low expansion(1.2%), and ultra low diffusion barrier (0.16/0.09eV), indicating rapid charge/discharge cycle capability.
Cathodes
Sodium-ion
Sodium-ion cathodes store sodium via intercalation. Owing to their high tap density,high operating potentials and high capacities, cathodes based on sodium transition metal oxides have received the greatest attention. To keep costs low, research attempts to minimize costly elements such as?Co,?Cr,?Ni?or?V.
A P2-type Na2/3Fe1/2Mn1/2O2?oxide from earth-abundant Fe and Mn resources can reversibly store 190 mAh/g at average discharge voltage of 2.75 V.
?A mixed P3/P2/O3-type Na0.76Mn0.5Ni0.3Fe0.1Mg0.1O2?was demonstrated to deliver 140 mAh/g at an average discharge voltage of 3.2 V?
In 2015.In particular, the O3-type NaNi1/4Na1/6Mn2/12Ti4/12Sn1/12O2?oxide can deliver 160 mAh/g at average voltage of 3.22 V.
A Na0.67Mn1?xMgxO2?cathode material exhibited a discharge capacity of 175 mAh/g for Na0.67Mn0.95Mg0.05O2. This cathode contained only abundant elements.?Copper-substituted Na0.67Ni0.3?xCuxMn0.7O2?cathode materials showed a high reversible capacity with better capacity retention.
Polyanions
Research has also considered cathodes based on polyanions. Such cathodes offer lower tap density, lowering energy density on account of the bulky anion. Among polyanion-based cathodes, sodium vanadium phosphate and fluorophospate?have demonstrated excellent cycling stability and in the latter, an acceptably high capacity (?120 mAh/g) at high average discharge voltages (?3.6 V?vs?Na/Na+)
Prussian blue and analogues
Several reports discussed the use of various? Prussian blue?and Prussian blue analogues (PBAs), with the patented rhombohedral Na2MnFe(CN)6?displaying 150–160 mAh/g in capacity and a 3.4 V average discharge voltage.
Electrolytes
Sodium-ion batteries can use aqueous?and non-aqueous electrolytes. The limited electrochemical stability window results in lower voltages and limited energy densities.
Non-aqueous?carbonate ester?polar aprotic solvents extend the voltage range. These include ethylene carbonate, dimethyl carbonate, diethyl carbonate, and oropylene carbonate. The most widely used salts in non-aqueous electrolytes are NaClO4?and?sodium hexaflurophosphate?(NaPF6) dissolved in a mixture of these solvents. In addition, NaTFSI (TFSI = bis(trifluoromethane)sulfonimide) and NaFSI (FSI = bis(fluorosulfonyl)imide, NaDFOB (DFOB = difluoro(oxalato)borate) and NaBOB (bis(oxalato)borate) anions have emerged lately as new interesting salts. Of course, electrolyte additives can be used as well to improve the performance metrics.
Difference between lithium and sodium
What Is a Sodium-Ion Battery?
Sodium-ion batteries are batteries that use sodium ions (tiny particles with a positive charge) instead of lithium ions to store and release energy. Sodium-ion batteries started showing commercial viability in the 1990s as a possible alternative to lithium-ion batteries, the kind commonly used in phones and electric cars.
With the advent of high-capacity Lithium Cobalt Oxide cathode material and Sony's successful demonstration of Lithium-ion cell fabrication processes Lithim-ion technology jump forward through out the world. Beyond 1990's almost the entire Battery's research community focussed their attention on the development of Lithium-ion Battery. Great progress was made in discovering, optimizing, and scaling up the Lithium-ion battery materials and processes.
However, since 2010, the battery research community has had a renewed interest in Sodium based cathode/anode/electrolytes. Over the past couple of years a completely new eco system is being developed around this chemistry.
More than 10 companies have announced commercialisation.
Faradion Limited
Faradion Limited, is a subsidiary of India's Reliance Industries. Its cell design uses oxide cathodes with hard carbon anode and a liquid electrolyte. Their pouch cells have energy densities comparable to commercial Li-ion batteries (160 Wh/kg at cell-level) with good rate performance till 3C and cycle lives of 300 (100% depth of discharge) to over 1,000 cycles (80% depth of discharge). Its battery packs have demonstrated use for e-bike and e-scooter applications. They demonstrated transporting sodium-ion cells in the shorted state (at 0 V), eliminating risks from commercial transport of such cells. It is partnering with AMTE Power plc (formerly known as AGM Batteries Limited).
On December 5, 2022, Faradion installed its first sodium-ion battery for Nation in New South Wales Australia
TIAMAT
TIAMAT spun off from the CNRS?CEA and a H2020 EU-project called NAIADES. Its technology focuses on the development of 18650-format cylindrical cells based on polyanionic materials. It achieved energy density between 100 Wh/kg to 120 Wh/kg. The technology targets applications in the fast charge and discharge markets. Power density is between 2 and 5?kW/kg, allowing for a 5 min charging time. Lifetime is 5000+ cycles to 80% of capacity.
HiNA Battery Technology Company
In December of 2022 it was reported?that a company named HiNa in partnership with Chines state-owned China Three Gorges Corporation, had started mass production of sodium-ion batteries. The first generation of HiNa batteries offer energy density figures of 125Wh/kg, which is around half that of lithium-ion batteries. However, these batteries are rated for around 4500 charge cycles, which is significantly more than typical lithium-ion batteries.
Typical lithium iron phosphate batteries offer energy densities similar to sodium-ion batteries, and the rated number of charge cycles is also similar. That puts sodium-ion batteries in direct competition with these batteries for applications such as backup inverter power or electric vehicles.
The next generation of these HiNa batteries are slated to have a 200Wh/kg energy density, and subsequent generations are expected to exceed that. Considering that some electric cars using lithium batteries have an energy density below 250Wh/kg, these early mass-produced sodium-ion batteries have serious potential to reduce the cost of power storage.
Natron Energy
Natron Energy, a spin-off from Stanford University, uses Prussian blue analogues for both cathode and anode with an aqueous electrolyte.
Altris AB
Altris AB was founded by Associate Professor Reza Younesi, his former PhD student, Ronnie Mogensen, and Associate Professor William Brant as a spin-off from Uppsala University, Sweden. The company was launched in 2017 as part of research efforts from the team on sodium-ion batteries. The research was conducted at the ?ngstr?m Advanced Battery Centre led by Prof. KristinaEdstrom at Uppsala University. The company offers a proprietary iron-based Prussian blue analogue for the positive electrode in non-aqueous sodium-ion batteries that use hard carbon as the anode. Altris holds patents on non-flammable fluorine-free electrolytes consisting of NaBOB in alkyl-phosphate solvents, Prussian white cathode, and cell production.
CATL
Chinese battery manufacturer CATL announced in 2021 that it would bring a sodium-ion based battery to market by 2023. It uses Prussian blue analogue for the positive electrode and porous carbon for the negative electrode. They claimed a specific energy density of 160 Wh/kg in their first generation battery. The company planned to produce a hybrid battery pack that includes both sodium-ion and lithium-ion cells.
The chemistry and electrochemistry of electrode materials for Na-ion batteries are sufficiently different from that of their Li-ion counterparts that candidates suitable for practical batteries have become available only recently. Figure 1 displays the schematic of a Na-ion battery cell.
It has a structure similar to that of Li-ion batteries. Laboratory test cells and representative prototype cells have been built and evaluated with hard-carbon anodes and cathode materials selected from layered transition metal oxides, transition metal fluorophosphates, and Prussian blue and its analogues
Sodium-ion batteries, also called Na-ion batteries, use a chemical reaction to store and release electrical energy. Like all batteries, they have two electrodes (a positive electrode and a negative electrode) separated by an electrolyte, which is a special substance that allows ions (tiny particles with a positive or negative charge) to move between the electrodes.
Sodium-ion batteries work similarly to lithium-ion batteries, but they use sodium ions instead of lithium ions. The choice of materials for the electrodes and electrolytes can affect the performance and lifespan of the battery, so researchers are constantly experimenting with different combinations to find the best combination of cost, performance, and safety. Generally, the cathode (the negative electrode) and electrolyte contain sodium.
When lithium batteries are charged through the electrolyte, lithium ions move from cathode to anode. Thus, charge balance is achieved, and discharge is just the opposite. In comparison, sodium ions move from the sodium-iron cathode to the carbon anode during sodium batteries charging through a liquid electrolyte. Just like lithium batteries, the discharge process of sodium batteries is opposite to the charging process.
WORKING PRINCIPLE OF SODIUM ION BATTERY
VIDEO LINK IS GIVEN BELOW
Sodium-ion batteries are devices that store energy by converting electrical and chemical energy into each other. The fundamental principle is very similar to that of Lithium-ion batteries, based on the reversible shutting of ions between the two electrodes with the help of electrolytes. A sodium-ion battery consists of a positive cathode + a negative anode electrode that are spaced apart by a separator and an electrolyte. The electrolyte contains a sodium salt dissolved in a suitable solvent mixture and enables the transport of sodium ions between the electrodes while being electronically insulated. Besides ionic conductivity the electrolyte must enable the formation of stable interphases at the electrode/electrolyte interfaces to prevent continuous electrolyte decomposition at high or low potentials. The electrolyte is in contact with several cell components, including current collectors, cell casing, the separator, the binders and thus must be compatible with all the items to achieve a long cycle life and safety standards.
A sodium-ion cell is typically assembled in the discharged state. The positive electrode is the sodium ion source of the cell and contains the transferable sodium-ion, where as the negative electrode is sodium free. Widely studied cathode materials are sodium transition metal oxides or Prussian blue analogs and anode materials are typically disordered carbons (hard carbons)
video link is given below.(SEI and CEI formation)
During the initial charge electrical energy is used to induce migration of electrons from the positive electrode to negative electrode via an external circuit. At the same time the positive electrode releases sodium ion into the electrolyte to maintain charge neutrally. The sodium ions are transferred to the negative electrode through the electrolyte to be inserted there into the active material. Accordingly an oxidation (positive electrode) and reduction (negative electrode) reaction takes place at the respective electrode. The cell voltage increases as the cell is charged. The most used electrolyte components have limited thermodynamical stability window and start to decompose at potentials above (positive electrode) or below (negative electrode) their electrochemical stability limits. As a result of electrolyte decomposition, interphases are formed from decomposition products at the electrode/electrolyte interfaces the CIA at the cathode and the SEA at the anode. The formation of these interphases is crucial for the functionality of the cell because they prevent continuous electrolyte degradation. To be efficient the interfaces must be electronically insulating but highly sodium-ion conducting.
Video link given below (Charge)
With ongoing charging more and more sodium ions are released from the cathode and stored in the anode via adsorption and intercalation mechanisms thereby the cell voltage gradually increases until the predetermined end of charge voltage is reached.
video link is given (discharge)
During discharge the movement of electrons and sodium ions are reversed and occurs from negative to positive electrode. In this case the oxidation reaction takes place at the negative electrode (cathode). The cell voltage decreases until the defined cut-off voltage.
video link is given (Rocking chair mechanism)
In each cycle the sodium ions are shuttled from positive to negative electrode (charge) and back (discharge). A high reversibility of the ongoing storage processes and high electrolyte stability are of crucially important requirement of long life of battery.
Key development directions of sodium-ion batteries
There are two key development directions for sodium-ion batteries, including the development of key technologies for ultra-long cycle life sodium-ion batteries and further improvement of the energy density of sodium-ion batteries.
Focus on the development of key technologies for ultra-long cycle life sodium-ion batteries, mainly including: electrode material crystal structure regulation, microstructure design, and preparation method optimization. Thus, a high-performance electrode material with stable structure, good uniformity, simple preparation process, and environmental protection is obtained.?
Another key development direction is to further increase the energy density of sodium-ion batteries (>200Wh/kg). The aim is to develop high-voltage cathode materials and phosphorus-based anodes or non-anode technologies to achieve the adaptation between high-voltage cathodes and low-voltage, high-capacity anode materials.
Solid-state sodium-ion batteries replace traditional electrolytes and separators, and on the basis of reducing the quality of sodium-ion batteries, strive to use metal-containing sodium composite negative electrodes to build high-voltage sodium-ion batteries. Bipolar battery and moduleless battery pack technology can effectively reduce the total mass of the sodium-ion battery energy storage system and increase the total energy density of the battery pack.
领英推荐
?What Makes Sodium-Ion Batteries Great?
Lithium-ion batteries rule the roost at the moment, and there's plenty of research to make them even better than they are right now. Still, sodium-ion batteries have a few distinct advantages over them.
The Drawbacks of?Sodium-Ion Batteries
There's no such thing as perfect battery technology, and there are a few reasons sodium-ion batteries haven't taken over from lithium yet.
Apart from these technical pros and cons, the manufacturing chain for sodium-ion batteries still has some kinks to sort out before it can become a widespread commercial product. Not to mention that engineers and scientists are working on solutions to this battery technology's remaining weak points. The Present and Future Potential of Sodium-Ion Batteries
Researchers and companies around the world are working to improve the performance and commercial viability of sodium-ion batteries. Some key areas of focus include improving the energy density and voltage of sodium-ion batteries, as well as increasing their lifespan and charge/discharge rate.
If these efforts are successful, sodium-ion batteries could become a viable alternative to lithium-ion batteries in the future. They could potentially be used in various applications, including portable electronics, electric vehicles, and stationary energy storage systems.
The fundamentals of Lithium and Sodium-ion battery electrochemistry were established In 2022, researchers at the US Department of Energy made a major breakthrough?in improving the durability of sodium-ion batteries. By changing some of the chemistry in the battery, the prototype coin-sized batteries lasted in excess of 300 cycles while maintaining more than 90% capacity. However, even without this new approach to chemistry, it seems that sodium-ion batteries are about to hit mass production anyway.
Sodium-ion vs. Lithium-ion Battery Technology
Sodium-ion batteries are a promising alternative to lithium-ion batteries — currently the most widely used type of rechargeable battery. Both types of batteries use a liquid electrolyte to store and transfer electrical energy, but differ in the type of ions they use.
An examination of Lithium-ion (Li-ion) and sodium-ion (Na-ion) battery components reveals that the nature of the cathode material is the main difference between the two batteries. Because the preparation cost of the cathode from raw materials is the same for both types of battery technologies, the main cost reduction for sodium-ion batteries comes from raw materials.
Factors Lithium-Ion Batteries Sodium-Ion Batteries Cost Expensive due to limited supply of lithium and high manufacturing costs Cheaper due to the abundance of sodium and lower manufacturing costs Performance Higher energy density and better electrochemical properties, suitable for portable electronic devices Lower energy density and higher internal resistance, better suited for grid storage applications and temperature extremes Size Smaller due to higher energy density Larger due to lower energy density Energy Storage Higher specific energy storage, up to 220 Wh/kg Lower specific energy storage, up to 40-200 Wh/kg Working Temperature Optimum performance between 15-35°C, works between -20°C to 60°C Optimum performance between 15-35°C, works between -20°C to 60°C, better suited for temperature extremes Cycling Stability Cycled up to 500 times at 80% depth of discharge Cycled up to 1000 times at 80% depth of discharge Self-Discharge Self-discharge rate of <5% per month Safer chemistry does not require cobalt Safety Can experience fire and explosion, requires cobalt which is toxic Can experience fire and explosion, and requires cobalt which is toxic Environmental Impact The self-discharge rate of <10% per month Easily accessible through conventional extraction techniques or seawater evaporation, lower carbon footprint alternative Requires lithium mining which has a high environmental impact and ethical concerns, significant pollution from mining operations Shorter charging time due to lower internal resistance and higher voltage Longer charging time due to higher internal resistance and lower voltage Comparison of Lithium-Ion and Sodium-Ion Batteries
Factors Lithium-Ion Batteries Sodium-Ion Batteries Cost Expensive due to limited supply of lithium and high manufacturing costs Cheaper due to the abundance of sodium and lower manufacturing costs Performance Higher energy density and better electrochemical properties, suitable for portable electronic devices Lower energy density and higher internal resistance, better suited for grid storage applications and temperature extremes Size Smaller due to higher energy density Larger due to lower energy density Energy Storage Higher specific energy storage, up to 220 Wh/kg Lower specific energy storage, up to 40-200 Wh/kg Working Temperature Optimum performance between 15-35°C, works between -20°C to 60°C Optimum performance between 15-35°C, works between -20°C to 60°C, better suited for temperature extremes Cycling Stability Cycled up to 500 times at 80% depth of discharge Cycled up to 1000 times at 80% depth of discharge Self-Discharge Self-discharge rate of <5% per month Safer chemistry does not require cobalt Safety Can experience fire and explosion, requires cobalt which is toxic Can experience fire and explosion, and requires cobalt which is toxic Environmental Impact The self-discharge rate of <10% per month Easily accessible through conventional extraction techniques or seawater evaporation, lower carbon footprint alternative Requires lithium mining which has a high environmental impact and ethical concerns, significant pollution from mining operations Shorter charging time due to lower internal resistance and higher voltage Longer charging time due to higher internal resistance and lower voltage Comparison of Lithium-Ion and Sodium-Ion Batteries
LIBs are known for their high energy density, which allows them to store a large amount of energy in a small volume. This property makes them suitable for use in portable electronic devices, electric vehicles, and grid-scale energy storage systems. However, the use of lithium in LIBs also makes them expensive and susceptible to thermal runaway, which can cause the battery to catch fire or explode.
SIBs, on the other hand, have a lower energy density than LIBs but are still considered to be promising alternatives. Sodium is more abundant than lithium and is therefore less expensive. SIBs also have a lower risk of thermal runaway than LIBs, which makes them safer to use. However, the lower energy density of SIBs means that they are not as suitable for use in high-power applications.
Due to the multiple advantages of sodium-ion batteries, large players in the energy industry are investing in acquiring and developing this technology. For example, Faradion, a battery technology company in the UK and an innovator in Na-ion battery, was recently acquired by Reliance New Energy Solar, a subsidiary of Reliance Industries, for $135 million.
Challenges for Sodium-ion Battery
Despite the advantages, sodium ion battery manufacturing needs to overcome several challenges before it can be widely adopted as a replacement for lithium-ion batteries.
Can Sodium-based Batteries Replace Lithium-ion Batteries?
Sodium-Ion Mass Production Has Already Started
In December of 2022 it was reported?that a company named HiNa in partnership with Chines state-owned China Three Gorges Corporation, had started mass production of sodium-ion batteries. The first generation of HiNa batteries offer energy density figures of 125Wh/kg, which is around half that of lithium-ion batteries. However, these batteries are rated for around 4500 charge cycles, which is significantly more than typical lithium-ion batteries.
Typical lithium iron phosphate batteries offer energy densities similar to sodium-ion batteries, and the rated number of charge cycles is also similar. That puts sodium-ion batteries in direct competition with these batteries for applications such as backup inverter power or electric vehicles.
The next generation of these HiNa batteries are slated to have a 200Wh/kg energy density, and subsequent generations are expected to exceed that. Considering that some electric cars using lithium batteries have an energy density below 250Wh/kg, these early mass-produced sodium-ion batteries have serious potential to reduce the cost of power storage.
However, just like LiFeP04 batteries, don't expect this technology in your smartphone or laptop any time soon. In these small devices, energy density is still the most important consideration. However, don't be surprised if your electric car or solar power battery system gets a little saltier in the near future.
Today, sodium-ion batteries are getting noticed as a possible alternative to lithium-ion batteries. With substantial investments in the technology by such global leaders as Contemporary Amperex Technology Co., Limited (CATL) and BYD heralding production on a large scale, sodium-ion batteries have sparked the interest of the automotive and energy storage industry.
Benefits and technology readiness
Sodium-ion batteries have many advantages over lithium-ion ones, such as better performance at lower temperatures and reduced dependence on the supply chain. These batteries offer a major advantage in cold temperature storage, since they perform really well even at such low temperatures as -10°C or -20°C. They also have high-power capabilities, using them to advantage in both energy and power applications, with the capacity of operating at 3C or 4C high-power rates. Besides, sodium-ion batteries can withstand extreme temperatures and humidity levels—which further enhances their appeal.
There are many players in the industry that are making tall claims about the long life of these batteries and are boasting about reaching over 4,000-5,000 cycles. Moreover, achieving the desired performance and life cycle compared to lithium-ion batteries remains a focal point for further development. Companies, such as CATL, BYD, HINA (China), Faradion (UK), Tiamat, North Volt (Europe),KPIT, NCL, CECRI and IIT-Roorkee (India), are actively involved in the research and development of sodium-ion.
A few companies have announced advancements in their sodium-ion products, but most are still between 5 and 6 of technology readiness levels (TRLs). However, they are yet to reach the required level of commercial production (TRLs 7-9). The choice of cathode and anode materials—which varies from company to company and can impact the general commercial readiness of the technology—is critical. CATL, HiNA and BYD, the key players, have already presented their progress with sodium-ion battery technology. For instance, the JAC Group, in collaboration with HiNa batteries, announced a vehicle launch only a couple of months ago.
Cost and energy density challenges
Cost is another significant factor hampering the commercial adoption of sodium-ion batteries. Although the industry aims to match sodium-ion battery price with lead-acid battery prices by 2025 or 2026, the cost at present is quite high, compared to Nickel-Manganese-Cobalt (NMC) batteries, or even higher. The cost of sodium-ion batteries depends upon the raw materials used. But the ongoing R&D efforts in anode and electrolyte technologies are likely to bring down the cost over time.
In the cell manufacturing supply chain context, Indian companies are learning from global platforms and realizing the importance of controlling the supply chain to reduce costs and, at the same time, ensuring good quality.
Despite a lot of excitement in the media about sodium-ion batteries as a game-changer, there are certain vital drawbacks that should be considered. In sodium-ion batteries, the energy densities are in the range of 100 wh/kg to 160 wh/kg and match the Lithium Iron Phosphate (LFP) performance at present. But to be able to reproduce and grow to meet large-scale demand, including producing one million sodium-ion cells for such a massive market as India, is still challenging.
Sodium-ion batteries go mainstream (Latest update)
Sodium-ion batteries are emerging as a viable alternative to lithium-ion technology. Industrial heavyweights CATL and Reliance Industries, following the acquisition of UK-based sodium-ion specialist Faradion, are bent on bringing the technology out of the lab and into mass production. Against a backdrop of soaring prices and predicted shortfalls of lithium-ion battery materials, sodium-ion chemistry has never been more tantalizing.
Giga fabs
On the last day of 2021, Indian conglomerate Reliance Industries said its solar unit would buy UK-based Na-ion battery technology pioneer Faradion for GBP 100 million ($136 million), including debt. The move marked Reliance’s sixth acquisition in the renewable energy sector. It was part of its ambitious?$10 billion plan to manufacture and fully integrate all “the critical components of the New Energy ecosystem,” spanning every stage of the solar supply chain, batteries, electrolyzers and fuel cells.
Under the plan, the conglomerate – which covers everything from textiles and polyester fibers to petrochemicals and petroleum refining – will build several gigafactories within India by 2024. As for its Na-ion manufacturing ambitions, Faradion CEO James Quinn told pv?magazine that the plan is to build a double-digit-gigawatt fab.
“I think it’s very clear that Reliance is really going all in on sodium-ion technology and building at giga factories level. And this is what the technology needs to be able to scale,” he said. “You need around 2,500 tons of cathode to do 1GW of cell manufacturing so the scale to go up into 10GW to 20GW is massive.”
Li-ion has had a head start of decades when it comes to production volume, reducing costs as it has scaled. But Quinn firmly believes that with Reliance and Faradion under the same roof, there is a unique opportunity to continue to innovate and advance the technology but at the same time scale it at a massive level.
“Their own captive requirement is so massive that that alone can significantly bring the cost down,” Quinn says. Reliance itself could have tens of gigawatts of captive requirements – it owns the largest telecom company in the world with 450 million subscribers, and has 22,000 trucks, to mention a few. In addition, the enterprise plans to build at least 100GW of solar projects by 2030, which it might decide to couple with batteries. “I think it’s the best chance for sodium-ion to really become mainstream,” Quinn says.
Faradion was the first company to champion Na-ion battery technology more than 10 years ago and back then had basically no competition. “We were really early in, so we put a web of IP around sodium-ion,” Quinn says. But interest has grown, and several companies have since emerged. They include HiNa Battery Technology (a spinoff from the Chinese Academy of Sciences), Tiamat (which came out of the French?National?Centre?for Scientific?Research), Natron Energy (a spinoff from Stanford University in the United States), Altris AB (started by a team from Sweden-based Uppsala University), and of course, China’s Contemporary Amperex Technology Ltd. (CATL) – the 800-pound gorilla in the battery industry.
Next generation
CATL released its first generation of Na-ion batteries in mid-2021, with plans to establish a basic industrial chain by 2023. At the launch, the Chinese battery manufacturer said it has been dedicated to the research and development of sodium-ion battery electrode materials for many years. It said its first generation of sodium-ion battery cells can achieve energy densities of up to 160Wh/kg and it is now aiming to exceed 200Wh/kg.
However, when asked by pv?magazine about improvements that will enable the jump in energy density announced for its second generation of sodium-ion batteries, CATL did not respond directly. It instead forwarded several local media reports as a suggestion for further reading. These articles speculated that CATL is working on anode-free metal battery technology, which will first be applied to the next generation of its Na-ion batteries, but not only limited to that space.
CATL has reportedly filed a patent named “Na metal battery, electrochemical device,” in which the metal layer formed on the negative current collector after the first charging is completed is used in place of the negative electrode. The absence of the anode from the manufacturing process, and its creation after the battery is assembled and charged for the first time, would be a unique advantage. It appears that CATL has not only laid out relevant material design patents, but also took the lead in applying for production process patents, which indicates that the research progress on this technology may be advanced.
Meanwhile, Faradion says it has already achieved a big jump in the energy density by virtue of cumulative iterative improvements on its cathode, anode, and electrolyte, and demonstrated a capacity of 190Wh/kg, which is now being transferred into production. In addition, the company is working on step change innovations, and as Quinn confirmed, expects to push the energy density towards 250Wh/kg. That would bring it on par with most Li-ion batteries today.
Powerful synergy
Ultimately, Na-ion will be a complementary technology to Li-ion, rather than a competitive one. The two battery technologies have much in common in terms of structure and working principles and can often even use the same manufacturing lines and equipment. Therefore, CATL is simply integrating its sodium-ion offering into their existing Li-ion infrastructure and product ecosystem.
“We have rolled out our AB battery system solution, which uses both sodium and lithium-based cells in one EV pack, thus helping leverage the benefits of both chemistries and opening up more room for application scenarios for sodium-lithium battery systems,” a CATL spokesperson said.
The system compensates for the current energy density shortage of the Na-ion cells and benefits from their performance in low temperatures. Faradion’s Quinn added: “You never put LFP in the same battery pack as NMC, you don’t really gain anything, but you can to this with Na-ion, it works like a supercapacitor, if you will.”
Conclusion
Sodium-ion batteries promise to be a viable alternative to lithium-ion batteries in a big way. Despite having made significant progress, sodium-ion batteries are yet to be easily available commercially. Its cost-competitiveness is another critical milestone that is far from reach of all battery stakeholders. With industry collaborations and ongoing research, the sodium-ion technology is expected to mature to finally establish itself as a reliable and sustainable energy storage solution for the future.