Even in 2011, Elon Musk, the CEO of Tesla Motors knew that capacitors would outstrip the battery in both performance and cost. While replacing batteries with capacitors is still out of the realm of possibility, a new capacitor may be able to work with the battery to store energy. Researchers at the Georgia Institute of Technology have developed just such a capacitor by finding the right material to make them with.
The research team had been searching for a material that that was dielectric, or one that does not conduct electricity well. Fortunately, that material is an abundant fatty acid called octylphosphonic acid that is already used in manufacturing for thing like corrosion inhibition.
Capacitors charge faster than conventional batteries, although they also discharge more quickly. They have longer lives as well, and don’t need to be replaced before the car is ready to be retired anyway.
Their new dielectric capacitors have only been tested at lab scale, so there will be plenty of future testing on actual electric cars before they will be found in driveways and parking lots across the country. The Georgia Tech team believes that their capacitor will test better than the current capacitor designs and some batteries currently being used.
To make the capacitor, the team used a sol-gel process that involves a solution of solid nanoparticles. The nanoparticles arrange themselves into a layer of octylphosphonic acid and a layer of bonded silica atoms, creating a gel. According to Georgia Tech, “the bilayer structure blocks the injection of electrons into the sol-gel material, providing low leakage current, high breakdown strength and high extraction efficiency”. In other words, the new material will make future electric car batteries both high capacity and longer lasting.
Image (c) John Toon, Georgia Tech