Scientists have found a way to significantly boost the capacity and effectiveness of energy storage devices called supercapacitors.
Future technologies reliant on large quantities of electricity could be revolutionised with the addition of an unexpected ingredient. In a paper published to Nature Materials, an international team of researchers from MIT and the University of Bristol said it has worked out a way to improve energy storage devices – called supercapacitors – using a new class of detergents related to laxatives.
These ‘ionic liquids’ have been found to be better electrolytes than current materials, such as aqueous and organic electrolytes, with a significant boost in performance. Despite being salts, ionic liquids exist in a non-solid state that makes them stable, non-flammable and often much more environmentally friendly.
Typically, for electrolytes in contact with a charged electrode, the distribution of ions is dominated by electrostatic Coulombic interactions. However, it’s possible to control this distribution by making the ionic liquids soap-like. This lets the molecules have separate polar and non-polar domains, similar to household detergents.
These soap-like electrolytes will then spontaneously form bilayer structures on the electrode surfaces, resulting in boosted energy storage capacity. The team also found that temperature and applied voltage affects the energy storage performance.
In terms of applications, the team said that it could be used for some of the more challenging tasks that require significant energy storage, such as oil drilling and space exploration. Also, it could pave the way for new and improved supercapacitors in hybrid cars.
Supercapacitors are essential components in modern hybrid cars and can outperform batteries in terms of higher power and better efficiency through regenerative braking, for example.
Using these new electrolytes, future supercapacitors may even be able to store more energy than batteries, potentially replacing lithium-ion batteries in applications such as electrical vehicles, personal electronics and grid-level energy storage facilities.
“To make this discovery required a team of scientists with a very diverse skill set, spanning chemical synthesis, advanced structural, microscopy and electrical techniques as well as computational methods,” said Prof Julian Eastoe of the University of Bristol, who co-authored the study.