A new formulation of lithium-ion batteries can increase battery life and possibly even double it. Batteries can also have a larger capacity, allowing them to store more energy.
This reports TU Delft in a paper recently published in the scientific journal Nature Communications. The researchers experimented with the composition of lithium-ion batteries. They found that adding some five salts to the batteries makes the formation of the protective layer between the electrolyte and both the anode and cathode more controlled.
Holding back electrons and letting lithium ions through
The protective layer plays a crucial role in lithium-ion batteries. The layer blocks electrons and instead allows lithium ions to pass through. These lithium ions transport energy in the battery. During charge cycles, the protective layer gets damaged and has to re-form each time. This process consumes lithium ions, which are therefore no longer usable in charging cycles. Consequently, the capacity of the battery decreases the more charging cycles a battery goes through.
A new composition of lithium-ion batteries enables new features. TU Delft researchers are adding five salts to the composition that makes up lithium-ion batteries. One of these salts was previously not usable for this purpose, as it does not dissolve well in the cocktail of substances exists.
Marnix Wagemaker, professor of electrical energy storage at TU Delft and lead author of the publication, is closely involved in the development. Wagemaker explains to De Volkskrant that the 'chaos' caused by the four remaining salts in the cocktail also causes the salt that previously did not dissolve well to do so now. Wagemaker speaks of a 'nice by-catch'.
Present in wide range of devices
The development could have a major impact on the use of lithium-ion batteries. Such batteries can be found in a wide range of devices. These include smartphones, tablets and laptops, as well as electric cars and bicycles. Batteries are relatively expensive and therefore play an important role in the overall cost of electrical devices.
TU Delft's invention may offer a solution. By increasing the lifespan and possibly even doubling it, batteries last longer. This makes battery replacement less frequent, which relieves the environment and also reduces costs.
New applications possible
Speaking to the Volkskrant, Wagemaker points to LeydenJar, a Dutch company developing batteries that can store more energy, among others. The company's batteries offer 70% more storage capacity. In practice, however, they can only be charged 450 times, whereas to be usable in electric cars, 800 charging cycles should be possible. Wagemaker expects TU Delft's technology to help bring this number closer.
Christian Rood, CEO of LeydenJar, confirmed to de Volkskrant that his company will test the TU Delft development. Rood says that the development could potentially contribute to an application for an electric car, but that testing is necessary.
Important step forward
Wagemaker is optimistic about the development. However, he does indicate that it is uncertain whether a doubling in lifetime is actually feasible. "Whether in practice a factor of two is feasible, I don't know. But even 20 per cent more is already a significant step forward and the chaos concept offers opportunities for further development," the professor tells the newspaper.
More information on the invention is available in the scientific journal Nature Communications, where a paper on their development has been published by the researchers.
Author: Wouter Hoeffnagel
Photo: VeComoHacerlo via Pixabay
