Science fair winner has 20.1 Wh/kg energy density core-shell nanorod supercapacitor

Eesha Khare, 18, of Saratoga, Calif., received the Intel Foundation Young Scientist Award of $50,000 for the invention of a tiny energy-storage device that will enable cellphones to charge in 20 seconds.

Eesha’s invention also has potential applications for car batteries.

The EEstory covers Eesha Khare and her parents.

Manoj Khare is her father. He was one of the co-founders of Vihana Inc., a company bought by Cisco for its semiconductor technology. It wasn’t a big company and the sales price was $30 Million. Manoj Khare has the material science background to account for the nearly miraculous high schooler’s invention.

Reena Khare (mother) is herself some sort of science genius and associated with a few patents in the biology realm (“genomic technologies”). It looks like she was part of a research team at Incyte Inc in a Palo Alto R&D facility before it closed.

Her teacher is Amanda Alonzo, who got a masters in something from Stanford. She won a California science teacher of the year award.

The Details of the Supercapacitor Work

Design and Synthesis of Hydrogenated TiO2-Polyaniline Nanorods for Flexible High-Performance Supercapacitors

The goal of this work was to design and synthesize a supercapacitor with increased energy density while maintaining
power density and long cycle life.

Methods/Materials

To improve supercapacitor energy density, I designed, synthesized, and characterized a novel core-shell nanorod electrode with hydrogenated TiO2 (H-TiO2) core and polyaniline shell. H-TiO2 acts as the double layer electrostatic core. Good conductivity of H-TiO2 combined with the high pseudocapacitance of polyaniline results in significantly higher overall capacitance and energy density while retaining good power density and cycle life. This new electrode was fabricated into a flexible solid-state device to light an LED to test it in a practical application.

Results

Structural and electrochemical properties of the new electrode were evaluated. It demonstrated high capacitance of 203.3 mF/cm2 (238.5 F/g) compared to the next best alternative supercapacitor in previous research of 80 F/g, due to the design of the core-shell structure. This resulted in excellent energy density of 20.1 Wh/kg, comparable to batteries, while maintaining a high power density of 20540 W/kg. It also demonstrated a much higher cycle life compared to batteries, with a low 32.5% capacitance loss over 10,000 cycles at a high scan rate of 200 mV/s.

Conclusions/Discussion

This project successfully designed, synthesized and characterized a novel nanorod electrode supercapacitor with increased energy density while retaining power density and long cycle life. This work is an important initial step in introducing this new electrode material in supercapacitors to replace conventional batteries in flexible electronic device.

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