The remarkable qualities of supercapacitors – high power density, high charging speed, long life and economy – promise them a bright life in a wide range of technical systems, from mobile and wearable electronics to electric vehicles. The creation of both an environmentally friendly, flexible, energy-intensive and safe supercapacitor is a problem that a group of scientists with the participation of representatives of Russia undertook to solve.
In a study published in the Journal of Energy Storage, scientists from Skoltech, Aalto University, and the Massachusetts Institute of Technology announced the creation of a high-performance, economical, and environmentally friendly elastic supercapacitor.
The development is based on sodium chloride (NaCl), which is in every kitchen, because this is ordinary table salt. A hydrogel in the form of a solution of sodium chloride replaced the ionic liquids commonly used in supercapacitors. The latter play the role of an electrolyte, often toxic to the environment. As for the electrolyte in the form of a solution of sodium chloride, it can be dangerous only in huge quantities and immediately.
“To increase the specific energy consumption of supercapacitors, ionic liquids are usually used, which are not only dangerous and environmentally harmful, but also significantly inferior in specific power to aqueous electrolytes with higher conductivity”– Tanya Kallio, a professor at Aalto University, notes one of the authors of the article.
Flexible current collectors (electrodes) based on films of single-walled carbon nanotubes (indicated by the abbreviation (SWCNT) in the illustration above) give elasticity to the new supercapacitor. The inner layer of the supercapacitor is made of a solid-state material in the form of plate electrodes made of graphene doped with nitrogen (NG). One of the elements filled with a hydrogel with sodium chloride The use of a hydrogel makes it possible to achieve a high specific energy consumption of a supercapacitor with a compact design without sacrificing the environmental friendliness of the electrolyte.
“We made a prototype in which productivity remained unchanged after thousands of tensile cycles at 50% deformation. The cost of manufacturing supercapacitors can be further reduced by using 3D printing and other modern manufacturing technologies, ” – said in conclusion, Skoltech professor Albert Nasibulin.
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