Salt Batteries: How They Work, Pros and Cons

We often hear about the salt batteries as eco-friendly and ecological alternatives, which should be used instead of the much more common and well-known ones lithium batteries. But what kind of technology are we talking about exactly? The term “salt battery” actually refers to a particular type of molten salt battery, a system that produces and accumulates energy in the form of heat (thermal batteries).

The “salt” one is not exactly a new or recent technology. This type of battery has been talked about for several decades, but until now the excessive production costs had greatly slowed down its diffusion. In terms of sustainabilityhowever, it seems that salt batteries could offer multiple advantages, as they would be less polluting and safer compared to lithium batteries.

But will it really be like this?

In this article we want to find out how salt batteries work, and we will see the pros and cons to consider before opting for this type of technology.

How do salt batteries work?

Among the devices belonging to this “family”, the batteries that they contain certainly stand out nickel and sodium chloride(the famous table salt), a completely natural element present in abundant quantities on Earth, even obtainable from sea water.

From a technical point of view, in the charged state salt batteries are composed of cells made up of a negative electrode of liquid sodium (anode) and a solid positive electrode of nickel and nickel chloride (cathode).

The two electrodes are separated by a ceramic tube or separator (beta-aluminate ceramic electrolyte). A molten secondary electrolyte (tetrachloroaluminate – NaAlCl4) is used to allow contact between the solid positive electrode and the ceramic electrolyte.

The operation of the salt battery is based on the achievement of very high temperaturesnecessary to trigger the chemical process. Usually, batteries therefore work at temperatures ranging give 270°C and 350°C.

What are salt batteries used for?

But all things considered, in which fields are sodium batteries used today? This technology could prove useful in various fields, such as electric and sustainable mobility (we often hear about salt batteries for cars and other means of transport).

Such devices can also be useful for theelectrical energy storage produced from renewable sources, such as wind power or as support for photovoltaic systems.

Pros and Cons of Salt Batteries

And at this point, let’s try to understand What are the advantages of salt batteries and accumulators?. Why should we prefer this type of battery instead of more classic ones, such as lithium batteries?

The advantages of this system are many:

• Almost total absence of substances dangerous and toxic to humans
• Possibility of producing energy starting from sustainable sources
• Availability of materials: Compared to lithium, sodium (one of the most abundant elements on the Earth’s surface) is certainly easier to obtain.
• Salt batteries can be easily recycled at the end of their life cycle, unlike lithium batteries, which contain a material that is more difficult to dispose of.
• The battery They work even at the most extreme ambient temperaturesfor example in areas where temperatures reach -20°
• Reducing the risk of accidents: Salt batteries do not present risks common to normal batteries, such as overheating, short circuiting or explosions
• Lifespan: These types of batteries They can work for up to 20 years before degrading, and do not require any particular maintenance.

Disadvantages to consider

Although it may seem like a very promising technology, salt batteries are not used on a large scale as one would expect. But why? Unfortunately, there are still some critical issues to address before this technology can be used more widely.

Among the disadvantages, one must consider:

• Timings: Once discharged, the battery takes approximately 200 hours to cool down and return to room temperature. Additionally, the system will take approximately 10-12 hours to return to its internal operating temperature when restarted. This means that the battery It is not suitable for fast and intermittent charges..
• The presence of the Nickel (20% of the total) requires the adoption of precautions at the time of disposal, as this metal is considered toxic.

You’re probably wondering How much does a salt battery cost?: you should know that both the production and the sale of these devices involve higher than average expenses. This is one of the reasons that have slowed down its diffusion. With a wider production, however, the costs could be more accessible for consumers.