Every once in a while, new technology seems to emerge spontaneously to change our world. Dynamite, penicillin, X-ray machines, and even microwaves are all examples of such new accidental discoveries.
Well, this year we might have had another one. However, this time it's not only going to revolutionize the way we live, but could save our planet from impending climate change: lithium-sulfur batteries.
For decades, we've been searching for the best technology to power our modern lifestyles and power every new technology, like electric cars. Since the early 90s, the battery technology has been lithium-ion.
They power everything, from phones and Teslas to grid backup facilities and even satellites. But despite the fact that they have happily taken us into the 21st century, they have some serious drawbacks.
First, the materials needed to make them, such as cobalt, are usually very harmful to the environment. They destroy vast ecosystems with toxic chemicals.
Then there is the problem του κύκλου ζωής. Απαιτούμε ταχύτερους χρόνους φόρτισης στις συσκευές μας. Αυτό ισχύει για τα πάντα, από τα τηλέφωνα μέχρι τα αυτοκίνητα. Όμως, όπως θα σας πει οποιοσδήποτε διαθέτει smartphone, οι μπαταρίες ιόντων λιθίου χάνουν πολύ γρήγορα την χωρητικότητά τους εάν τις φορτίζετε επανειλημμένα.
Battery degradation is a very serious problem, particularly for the EV world. Used EVs can sometimes be useless if the battery dies, which will cost a small fortune to replace. Overall, this slows the adoption of electric vehicles. Of course, changing the battery also means electronic waste, which is already a significant problem.
There is also the problem of density. Li-ion packs are relatively energy dense, but still very heavy, large and bulky. This limits the range of electric cars because the batteries are so heavy. This makes the use of batteries impossible for some applications, such as commercial electric airplanes.
There is even the problem of fire with lithium-ion batteries, as a damaged cell can cause a fire which is very difficult to extinguish.
These are the reasons why scientists at Drexel are looking for a new type of battery.
The batteries lithium-sulfur they seem to solve all the problems of lithium ion. They use far less ecologically harmful materials, can be cheaper to produce, can be up to three times more energy dense (which means lighter batteries) and are far less likely to catch fire. All this without any loss in charging speeds.
So what's the problem? Why don't we already have them?
They have a huge problem. While a lithium-ion battery can be used for about 2000 charge cycles, lithium-sulfur batteries are typically limited to half that. So after a year or two of proper use, a lithium-sulfur battery stops working.
To solve this, the team of Drexel was trying new approaches, changing the compounds in the battery's cathode.
Their goal was to slow down the chemical reaction that creates polysulfides when the battery is charged and discharged. These crystals remove sulfur from the electrode and eventually cause a huge loss of capacity. Slowing it down could make these very energy-dense batteries last longer.
What they found was something incredible: a chemical sulfur phase that effectively stops battery degradation! They were so shocked by this discovery that they had to check her 100 times to make sure.
This chemical phase is also known as the monoclinic gamma-sulfur phase, but it had only been observed in the laboratory at very high temperatures — above 95°C. This was the first time it was observed at room temperature.
In this phase the battery completely stops the reaction that creates polysulphides. This was so efficient that the scientists were able to perform 4.000 charge cycles without a drop in capacity, which means it lasts at least twice as long as lithium-ion batteries.
It's also worth noting that their battery was three times more energy dense than lithium-ion and could charge just as fast!
As with most serendipitous discoveries, scientists have not yet figured out what is actually going on. They don't yet know why this sulfur phase is created or how they can make sure it stays that way. So further research is needed to answer these questions in order to develop a reliable battery that can be used in billions of computers, electric cars and more.
The wait will be worth it as these batteries will weigh a third of their Li-ion counterparts and last twice as long!
Lithium, sulfur, and the other materials needed for this new battery are abundant throughout the Earth. This means we can drastically minimize its ecological impact minings, as well as to ensure a stronger supply chain.
However, the Drexel team is already looking at using this breakthrough to make sodium-sulfur batteries. By eliminating the need for lithium, they will be able to make batteries even more environmentally friendly and remove a huge bottleneck from the supply chain, ensuring EV adoption can continue at the breakneck speeds automakers plan.
This serendipitous discovery from Drexel will revolutionize the world's energy use and help humanity transition to a cleaner, carbon-neutral society. Hopefully the Drexel team can get this technology out of the lab and into our hands soon.
