Eesha Khare, a 18 years schoolgirl educated in a school in Silicon Valley in California, won an award May 17 during the competition "Intel International Science and Engineering Fair 2013" and received a $ 50 000 check for his supercapacitor project.
"A high school student creates a super capacitor to recharge a smartphone in 20 seconds." It is with such catchy title that some media announced the news. If the feat of the girl is real, it is an exaggeration to say that she has invented a sufficiently high performance supercapacitor to replace our Smartphone battery. The work of the young girl especially show that research on supercapacitors moving fast, and that in future they might advantageously replace some batteries.
Supercapacitors are kind of fastest batteries that can allow to recharge a smartphone in 20 to 30 seconds. It still lacks the supercapacitor to dethrone the batteries, it is a better energy density to last longer for a weight and a given volume (Recharge your phone in 20 seconds is not very interesting if need to recharge 2 or 3 times a day in return).
Ultracapacitors currently marketed offer an energy density of 4 to 6 Wh per kg. Large customers in the aerospace and defense industry are entitled to supercapacitors 9 to 10 Wh per kg as SkelCap Series Skeleton Technologies.
The high school student has succeeded in developing an even more powerful supercapacitor with an energy density of 20.1 Wh per kg. It is a real achievement that can enable higher penetration of ultracapacitors on the market if the technology was rapidly becoming marketable.
But even more powerful supercapacitors have already been created in laboratories and in various more or less promising techniques. The best performing supercapacitor created to date offers an energy density of 150 Wh per kg! A density that can be achieved only in laboratory conditions but which shows that supercaps can be largely improved.
Lead acid batteries provide an energy density of 20 to 40 Wh per kg, while the lithium-ion batteries are between 150 and 200 Wh per kg.
The supercapacitor created by Eesha Khare
The supercapacitor developed by Eesha Khare provides outstanding longevity like all ultracapacitors, with only 32.5% loss in capacity after 10,000 charge / discharge cycles (the cell phone batteries guarantee a smooth operation for only 400 to 1000 cycles). Some supercaps can withstand 20 million charge cycles.
The supercapacitor of Eesha Khare offers a power density of 20,540 W per kg (rapidity of charge). On this point, the SkelCap Series do better with about 48,000 W per kg.
Technically, to improve the energy density of supercapacitor, Eesha Khare designed, synthesized and characterized a novel electrode nanorods with hydrogenated titanium dioxide nuclei (H-TiO2) and shells polyaniline (PAni), a conductive polymer . Hydrogenated titanium dioxide then acts as an electrostatic double layer. The good conductivity of TiO2 hydrogenated combined with the pseudo-high capacity of the polyaniline gives a total capacity and a significantly high energy density while maintaining good power density and long life.
To perform its work, the high school girl had access to laboratory facilities of the University of California Santa Cruz under the supervision of Mr Yat Li. Work on ultracapacitors based on hydrogenated titanium dioxide nanorods were yet published in February 2012 in the journal Nano Letters: Hydrogenated TiO2 Nanotube Arrays for Supercapacitors.
The supercapacitor created by Eesha Khare is small and flexible and has been used so far only to turn on the LED for testing purposes. Bulkier versions will in future operate electronic appliances and why not smartphones.
The young high school girl sees further and is already planning a version of its super capacitor to replace car batteries. Version reduced size, supercapacitor could also enjoy its finesse and its flexibility to be inserted directly into the flexible OLED screens that will soon hit the market, or in smart clothes which will then be powered by photovoltaic films.
Meanwhile, Eesha Khare decided to use his $ 50 000 price to fund part of his studies at Harvard. The high school may have other opportunities to find funding for his studies because it is necessarily marked by Intel who handed him his price, but perhaps also by Google that would focus closely on its research according to the Financial Express.
Eesha Khare discusses his supercapacitor: