First Breakthrough in Batteries in 200 Years: Nanotube Ultra-Capacitors

Cambridge, MA - Traditional batteries haven't progressed far beyond the basic design developed by Alessandro Volta in the 19th century. But work at MIT's Laboratory for Electromagnetic and Electronic Systems (LEES) holds out the promise of the first technologically significant and economically viable alternative to conventional batteries in more than 200 years.

Researchers at MIT's LEES Laboratory are using nanotube structures to improve on an energy storage device called an ultracapacitor.

Capacitors store energy as an electrical field, making them more efficient than standard batteries, which get their energy from chemical reactions. Ultracapacitors are capacitor-based storage cells that provide quick, massive bursts of instant energy. They are sometimes used in fuel-cell vehicles to provide an extra burst for accelerating into traffic and climbing hills.

However, ultracapacitors need to be much larger than batteries to hold the same charge.

The LEES invention would increase the storage capacity of existing commercial ultracapacitors by storing electrical fields at the atomic level.

Continued at Fuel Cell Works

The new nanotube-enhanced ultracapacitors could be made in any of the sizes currently available and be produced using conventional technology.

"This configuration has the potential to maintain and even improve the high performance characteristics of ultracapacitors while providing energy storage densities comparable to batteries," Schindall said. "Nanotube-enhanced ultracapacitors would combine the long life and high power characteristics of a commercial ultracapacitor with the higher energy storage density normally available only from a chemical battery."

AP-SWNT's = 50/gram
RFP-SWNT's = 250/gram

Introduction
Ultracapacitors or double layer capacitors (DLCs) are
energy storage devices whose operation is based on the double
layer effect [1]. By utilizing highly porous carbon material with a
surface area up to 2000m2/g as electrodes (as in Fig. 3) commercial
DLCs can achieve a energy density (6Wh/kg) much greater than the
energy density of a conventional capacitor. However, this figure is
much lower than the energy density reached by Lithium-Ion batteries
(120Wh/kg).
..................
Fig. 2 - right) as electrode structure, can lead to an ultracapacitor
characterized by a power density greater than 100kW/kg (three
orders of magnitude higher than batteries), a lifetime longer than
300,000 cycles, and an energy density higher than 60Wh/kg.

Carbon Carbon Nanotube Nanotube Enhanced Enhanced Ultracapacitor