Most of the rechargeable batteries used in today’s technology, from electric cars to pocket phones, are lithium-ion (Li-ion) batteries. Since its inception in the early 1990s, lithium-ion battery technology has been widely adopted due to its high energy density, lightweight construction, and ability to provide high voltage on demand to equipment, vehicles, and more.
But scientists are working on new candidates that threaten to relegate lithium-ion to the past, at least in certain applications. Sodium-ion (Na-ion) batteries (sometimes referred to as NIB, an abbreviation for Na-ion batteries) are a new battery technology that stores charged sodium ions in the battery’s electrodes, rather than lithium ions as in lithium-ion batteries.
you may like
Scientists working on the technology also say that Na-ion batteries have inherent safety benefits and could make them more convenient for large-scale static battery setups.
Comparing Na-ion and Li-ion batteries: What are the advantages?
The main advantage of Na-ion batteries is that they are cheaper, easier and more sustainable to manufacture due to the abundant availability of sodium.
“Sodium, in particular, is cheaper, more abundant, and less geographically concentrated than lithium,” explains Dustin Bauer, an associate at intellectual property firm Ready & Growth, who has a Ph.D. studying the synthesis, composition, and use of sodium-ion and lithium-ion batteries.
Because of the operating voltage of the battery, lithium-ion requires the use of copper for the negative current collector, but copper is more expensive and heavier than aluminum.
Carmen M. López, Chief Scientist in the Electrochemistry Group at the National Physical Laboratory (NPL);
Given the potential pitfalls of global supply chains that have been exposed over the past decade, and climate change goals that require a mass switch to electrification and transportation wherever possible, there are clear advantages to adopting batteries that do not rely on hard-to-find critical minerals to function.
“For reference, sodium is the sixth most common element on Earth, with a natural abundance of 2,360 mg/L, while lithium, at number 32 on the list, has a natural abundance of 20 mg/L,” said Carmen M. López, chief scientist in the Electrochemistry Group at the National Physical Laboratory (NPL).
Once the supply chain for Na-ion batteries is up and running at scale, costs could drop significantly compared to lithium-ion batteries, flooding the global market with more affordable energy storage options. For example, CATL, the world’s largest battery manufacturer, recently began commercial production of Na-ion batteries for heavy-duty vehicles.
In addition to using silicon for the battery’s positive electrode, the Na-ion battery chemistry also avoids the need for other expensive components.
What to read next
“Due to the operating voltage of the battery, lithium-ion requires the use of copper for the negative current collector, but copper is more expensive and heavier than aluminum,” Lopez said.
He added that sodium-ion batteries have the potential to replace the organic electrolyte used as the conduction medium for ions in lithium-ion batteries with an aqueous electrolyte. This makes battery production more sustainable and cheaper.
Battery chemistry is also at the center of safety claims regarding Na-ion batteries. Thermal runaway (an exothermic chain reaction that occurs within a battery cell and can cause a fire) is less likely to occur in Na-ion batteries than in Li-ion batteries.
This is because sodium ions are larger than lithium ions, so they have more “friction.” As a result, if damage occurs that could lead to thermal runaway, it will flow to the point of impact at a rate that is less likely to cause rapid temperature increases. Lithium ions, on the other hand, flow quickly and can cause overheating, release of oxygen, and ignition.
Finally, Na-ion batteries have improved heat resistance compared to Li-ion batteries due to their lower volatility and lower electrolyte viscosity. In other words, this refers to a decrease in performance at low temperatures due to the lower charge density of sodium ions compared to lithium ions, and the ions continue to move freely even at low temperatures.
In a recent study published Dec. 12 in the journal Chinese Chemical Letters, scientists from Hunan First Normal University and Central South University found that lithium-ion batteries can only maintain 20% of their room-temperature energy capacity when tested at -4 degrees Fahrenheit (-20 degrees Celsius). The researchers noted that with further testing, Na-ion batteries could offer better performance.
Can Na-ion batteries be used in EVs?
Na-ion batteries are low cost and safe, making them suitable candidates for EV batteries. First and foremost, as the world increases EV adoption, with 39 countries accounting for more than 10% of EV sales share by 2025, according to energy think tank Ember, it will require a more sustainable and scalable supply chain for vehicle batteries.
The production of Na ions, if achieved at scale, could be highly localized, allowing factories in most parts of the world to capture or synthesize the hard carbon that forms the backbone of devices.
Additionally, data from National Car Charging shows EV batteries may be safer by reducing the chance of thermal runaway occurring within Na-ion batteries. EV batteries currently burn at a similar rate to gasoline or diesel fuel.
However, no technology is perfect, and it is unlikely that Na-ion batteries will replace all Li-ion batteries any time soon. This is because the drawbacks of Na ions make them a more situational alternative to the lithium-based batteries we are all familiar with.
First and foremost, Na-ion batteries have lower energy density than Li-ion batteries. This is the same reason why it has a low viscosity. Sodium ions are simply larger than lithium ions, which reduces the overall movement that occurs within the electrolyte of a Na-ion battery and is converted into electricity.
According to the American Physical Society, sodium has three times the mass of lithium, which means that each gram of Na-ion batteries holds less charge.
In practice, this means that Na-ion batteries cannot compete with Li-ions in terms of the amount of energy they hold. The same data from the American Physical Society cites the average energy density of lithium-ion batteries to be in the range of 100 to 300 watt-hours per kilogram. In contrast, CATL’s first generation Na-ion battery achieved a figure of only 160 Wh/kg.
Na-ion batteries have an inherently lower energy density compared to lithium-ion batteries, which is a major barrier to using Na-ion batteries in EVs, despite their potential safety benefits. Bauer says energy density issues are the “major and perhaps decisive” drawback of Na-ion batteries, and it’s clear that researchers are working hard to overcome this challenge.
“There’s a lot of discussion going on in the battery industry about this,” Lopez told Live Science. “Due to power and energy density limitations, the size and weight of Na-ion batteries required to power typical electric vehicles would not be suitable for onboard deployment.The best potential for transportation is [be] with slow charging infrastructure and/or ultra-compact short-range vehicles. ”
Lopez added that the disadvantages of Na ions’ lower energy density are not completely offset by lower cost and weight due to the simpler, lighter-than-copper design. Therefore, the economics of some Na-ion batteries just don’t add up at the moment.
All this means that Na-ion batteries are currently more suitable for static systems and are therefore not the first choice for EV batteries. However, this is far from a niche market.
Grid storage beckons
In fact, one of the most promising use cases for Na-ion batteries, corroborated by experts LiveScience spoke to, is in grid-scale energy storage, such as battery energy storage systems (BESS).
These vast batteries are becoming increasingly important to the stability of national and regional power grids, especially for storing intermittent production of renewable energy such as solar and wind power for later use.
For example, the UK Parliament investigated the risk of system-wide BESS thermal runaway, citing fires at BESS facilities associated with both the Liverpool and Essex processes.
However, even considering the low initial cost of Na ions, energy density remains a drawback of this technology when it comes to energy storage. For example, EV and battery giant BYD’s Na-ion BESS product, MC Cube-SIB ESS, delivers an energy storage capacity of just 2.3MWh in a 20-foot size configuration, as reported by Energy Storage News. This compares to about 6.4 MWh for BYD’s lithium-ion products in the same lineup.
Bauer cited the Baochi Reservoir in Yunnan province as an example of where both lithium and sodium ions are used to store renewable energy on a large scale. The reported main benefits of this approach include faster battery discharge (six times faster than current battery models, according to the Global Times) and improved resilience in weather conditions from -4 to 113°F (-20 to 45°C).
When will Na-ion batteries be commercially available?
Although Na-ion research is ongoing and new breakthroughs will help improve the energy density of Na-ion batteries, this is a mature research area with great commercial potential. In fact, we are already seeing manufacturers launching products with Na-ion batteries.
“Commercial production is already underway and initial mass production capacity is operational,” Bauer said.
“CATL, the world’s largest lithium-ion battery manufacturer, introduced the Naxtra passenger EV NIB with an energy density of 175Wh/kg and Freevoy, a mixed ion (mixed NIB and LFP lithium-ion) battery, in 2025. More recently, CATL introduced the Tianxing II, a ‘high volume’ NIB for light commercial vehicles.
Nevertheless, Lopez cautioned that more real-world safety testing of Na-ion batteries needs to be completed: “For example, is it more desirable and viable to deploy these batteries in urban versus remote environments? How do they fit into existing power infrastructure? There are particular considerations,” she said.
Source link
