Can Li-S batteries replace Li-ion batteries in electric vehicles?
Electric Vehicles (EVs) and their battery-powered systems are starting to play a very important role in today’s automotive industry.
EVs are built with a number of different battery systems all of them with different qualities and it can be hard to decide which one fulfills best all the most important characteristics such as design, cost, energy storage efficiency, safety and utilization life.
However, some international commentators seem to think that, when looking at lithium-ion batteries, we are getting very close to the energy density limit that this technology can reach.
If in the forthcoming years we want to improve drastically batteries capabilities, companies will have to develop new battery chemistry very different from the traditional ones. For this reason, researchers are on a hunt for new materials that can be used improve further charge capacity.
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What’s a Li-S battery?
New battery developed with the use of sulfur instead of the conventional lithium-ion could potentially have a 3 to 5 times higher charging capacity, allowing for massive increase in terms of the driving distance.
Also, in terms of production costs, lithium-sulfur batteries could also have an advantage as sulfur is cheap and relatively abundant material, being a by-product of the petroleum industry.
Currently, the top Li-S batteries can offer specific energies on the order of 500 W·h/kg, considerably better than most lithium-ion batteries, which, at the moment are in the range of 150 to 200 W·h/kg.
Li–S batteries with up to 1,500 charge and discharge cycles have also been currently tested.
However, batteries developed with this kind of new Lithium-sulfur technology can suffer from fast capacity decay and short cycle life as the sulfur intermediates can leak out into the electrolyte as the battery operates.
Sulfur can also expand about 80% during charging and discharge causing obvious design issues that need to be addressed
For these reasons the commercialization of the new batteries is still at the beginning although a big company such as Sony, which interestingly commercialized also the first lithium-ion battery, plans to introduce lithium-sulfur batteries to the market in 2020.
It’s also interesting to notice how this technology has been already successfully used in some experimental projects like the longest and highest-altitude solar-powered airplane flight in August 2008.
Other use of Li-S batteries
The main issue when using Renewable Energy is their intermittency – we lose solar energy at night and wind energy when the meteorological situation is not favorable.
In recent years microgrids (solar PV + energy storage) have become a popular solution for homeowners that want to resolve the issue of renewable energy intermittency. However, this solution can still be an expensive one for some people.
In an ideal world, when Renewable Energy becomes more widely used, the energy grid we will need massive, high capacity, long-lasting batteries that can store store solar energy during daytime and transfer it again at night into the main energy grid and, in turn, into our homes and industries.
Li-S batteries could potentially resolve this issue and present a technology that could offer a have energy storage solution for the entire electric grid.
Transition to Li-S technology
As already mentioned, the lithium-sulfur technology is still in its infancy. Researchers still have to gain a better understanding of the fundamentals of these systems in order to improve their performance and safety.
However, some commentators seem to believe that there will be a slow transition into this new technology and that, in the next 5 to 10 years, it will become more widespread.