Supercapacitors charge almost immediately and release a lot of power when needed. If they can hold more energy, they can completely eliminate the electric car’s Achilles heel – the slow charging time. Now, scientists in China and the UK say they have found a way to store 10 times more energy per volume than previous supercapacitors.
A team of researchers at University College London and the Chinese Academy of Sciences has released a study that demonstrates the concept of a new supercapacitor design that uses graphene laminates and focuses on the spacing between layers, which researchers have found can radically increase energy density. They precisely adjusted the size of the holes in the membrane based on the size of the electrolyte ions.
Using this design could significantly increase the volume of energy density, the team said. The new design has passed a record 88.1Wh/l test when commercial technologies like fast charging tend to provide about 5-8 watt hours of electricity per litre. The team claims to be the highest energy density ever for carbon-based supercapacitors.
This number is close to the high-end storage of typical lead-acid batteries, but lead-acid batteries charge very slowly and have low power density, but supercapacitors can be recharged very, very quickly and provide a huge power density of about 10 kW per liter. In addition, supercapacitors appear to have a long life, maintaining 97.8% of their energy capacity after 5,000 cycles, and are flexible, bending 180 degrees almost identical to flat.
But supercapacitors have three drawbacks. The first is that these supercapacitors are still much denser than the top lithium-electric EV batteries. The estimated value of the Tesla lithium battery pack is 877.5 Wh/l, which means that the supercapacitor must be 10 times the size of the Tesla battery pack to provide the same mileage. Second problem: Supercapacitors tend to leak energy rather than store it well. Third point: This is made of graphene, but so far no one has mass produced graphene at a viable price.