Sodium-Ion Batteries

 Sodium-Ion Batteries : Future of the world in Battery Technology

There always seems to be some new "revolutionary" battery technology just around the corner, but they never materialize in actual products used by us. It's not the case for sodium-ion batteries, which are already making an impact, and are likely to be something you'll depend in the near future. Sodium-ion batteries present a promising alternative to Lithium-ion technology, leveraging similar electrochemical principles while using sodium instead of lithium. These batteries offer the potential for sustainability and cost-effectiveness, making them increasingly relevant in today’s energy storage landscape. There's a good chance you haven't even heard of this technology until this very moment, so it might seem like it's just appeared out of nowhere, but actually sodium-ions have been a promising area of interest for quite some time. Now, thanks to several important breakthroughs, the age of salt is here.

Sodium-ion and Lithium-ion batteries share fundamental chemistries but differ in key materials and configurations. Sodium-ion cathodes include transition metal oxides, polyanions and Prussian blue analogues. Transition metal oxides contain sodium, oxygen, nickel, iron and manganese, while Prussian blue analogues use sodium, iron, carbon and nitrogen. These unique cathode compositions eliminate reliance on cobalt, a rare and costly material, and prioritize affordability. Lithium batteries power our world. Their power density make devices like smartphones and laptops feasible. Most electric vehicles use them too. However, they come with a long list of downsides too; high material costs, fragile supply chains, environmental issues and ethical and political ones also. It's becoming increasingly clear that if we're going to move completely to renewable energy (which has to be stored) and leave ICE vehicles behind, then lithium battery technology can't really be scaled effectively. We need batteries based on something abundant and widespread. We need batteries which are safer and more stable than notoriously volatile lithium-ion chemistry. So it's where the sodium-ion (Na-ion) battery comes into play.

Sodium-ion batteries exhibit impressive characteristics compared to their lithium counterparts. Although their energy density trails behind nickel-based Lithium-ion cells, it parallels high-power lithium iron phosphate (LFP) batteries. Notably, sodium-ion cells achieve a remarkable power output of approximately 1000 W/kg. This surpasses NMC cells’ 340–420 W/kg and LFP cells’ 175–425 W/kg performance. Additionally, sodium-ion batteries excel in cold-temperature conditions, offering reliable energy storage even in challenging climates. Na-ion batteries won't (and really shouldn't) replace Li-ion batteries entirely. It's best to use a technology where it makes the most impact with the fewest downsides, and for Na-ion batteries, which includes the following:-

Low-energy, high-cycle devices such as power banks, e-tools and some IoT applications benefit from long cycle life and wide operating temps.

Grid energy storage. We need lots and lots of energy storage. Especially to buffer against renewable energy's vagaries.

Hybrid applications. There are some interesting designs which mix lithium and sodium cells. Especially for EVs. This lets you create a hybrid battery which can lean on the strong suits of both battery types.

Light EVs and city cars. If we want everyone to change over to EVs, we need to make the batteries cheap, abundant and improve the lifespan and extreme temperature performance. EVs might be the best use case for Na-ion.

The basic principles of a sodium-ion battery are the same as a lithium-ion battery. It's just that we're using a different material to shuffle ions from one terminal to the other. Sodium is hugely abundant, cheap and easy to extract, and you can find it anywhere in the world. It's not just the sodium. Iron and manganese are good materials for sodium-ion cathodes, and these are cheap and abundant materials. In comparison to the expensive and relatively rare nickel and cobalt used in lithium-ion batteries, and you'll start to get the picture. Na-ion batteries are far safer than Li-ion ones. This makes them attractive for EV batteries, for example, where you don't want your batteries to explode in a crash. Na-ion batteries also perform better in low-temperature environments. That's good, because some parts of the world can't currently use Li-ion EVs, because it's too darn cold! One of sodium-ion batteries’ standout benefits is their cost-effectiveness. A Sodium-ion Battery designed with a layered metal oxide cathode and hard carbon anode can reduce material costs by 25-30% compared to LFP batteries. This affordability stems from replacing lithium and copper with sodium and aluminium, significantly cutting expenses. Aluminium as the current collector alone contributes to a 12% cost reduction, enhancing the economic appeal of sodium-ion configurations.

So if Na-ion batteries are so great, why haven't we been using them earlier. Well as you might expect, there were issues with these batteries that made them unsuitable, until now. Energy density was a big one. There's no point in needing twice the amount of battery for the same power, especially in something like a car. However, modern Na-ion batteries now have energy densities comparable to some Li-ion EV batteries. China’s CATL, the world’s largest battery maker, launched its second-generation sodium-ion platform, Naxtra, reporting an energy density around 175 Wh/kg and mass-production plans. CATL touts improvements in cycle life and safety which make Naxtra comparable to LFP batteries for many passenger EV applications. It's still short of the best Li-ion batteries in EVs which offer north of 100 Wh/kg, but it's good enough to make it feasible. Besides, if the batteries are cheaper, you can add more of them to increase range. While Lithium-ion prices continue to decline, Sodium-ion Battery development hinges on engineering advancements rather than just large-scale production. Innovations in sodium-ion technology could significantly lower costs and broaden its applications. These advancements may position sodium-ion as a complementary option to Lithium-ion, particularly in areas where affordability and abundant resources are vital.

It's not just China that's making big moves. Natron Energy announced a planned $1.4 billion sodium-ion gigafactory in North Carolina (a move intended to build domestic supply and lower reliance on overseas production). Factory plans and other public investments like this are critical because battery costs collapse when manufacturing scales. The USA doesn't have to import sodium or iron. Though manganese isn't mined commercially in the USA. We're not just talking EV-scale batteries here. As seen in New Atlas, Japanese hardware maker Elecom launched what it calls the first consumer power bank using a sodium-ion cell, marketed for dramatically longer cycle life and broader operating temperatures. Sodium-ion technology is ideal for applications requiring affordable energy storage and sustainability. With on going engineering progress, sodium-ion batteries may soon offer viable alternatives, enriching energy storage systems across industries. Their distinct chemistry and lower costs make them a valuable addition to the growing arsenal of energy storage solutions. While some form of Na-ion battery now seems to be ready to be placed in our cars and electronics, there's a lot of work to be done to improve these batteries even more. These include improvements in anode materials, electrolyte formulations and “anode-free” or reduced-graphite designs which improve energy density and lifetime. Of course, Li-ion technology is also advancing, with products like an anode-free lithium metal battery, but that still looks like a problematic element.

New research suggests cell-level costs could fall to around US$40/kWh at scale for mainstream Na-ion chemistry using iron/manganese cathodes. That's way below the cost of Li-ion, and analysts expect that the demand for Na-ion batteries will skyrocket as EVs become more popular and come down in price, partly thanks to these cheaper batteries. Sodium batteries are likely to become a major complementary technology to Li-ion batteries, which will reduce the scarcity and supply pressures on lithium technologies. Na-ion battery technology could even take over completely for Li-ion if it becomes too expensive or too hard to get the materials, but only time will tell how the geopolitics take a shape. For now, a revolution in large-scale battery technology for cars, grid storage and home power stations, and the factories to pump out these batteries are already on the way. By reducing dependency on rare materials and offering competitive performance, sodium-ion batteries pave the way for broader adoption. Their scalability and affordability ensure a promising future in the quest for sustainable energy storage around the world.