Power Electronics
Nano Technology Promises Better Batteries and Fuel Cells

Nano Technology Promises Better Batteries and Fuel Cells

QuantumSphere, a manufacturer of nano metals and alloys, has been awarded a U.S. patent for its method of manufacturing advanced nanomaterials. Metals and alloys produced in this process are ultrapure, highly uniform, and less than 50 nanometers in size. These qualities result in highly active materials with high surface area, which the company says will cut costs and enable dramatic improvements in battery and fuel cell electrode performance and on-demand hydrogen generation. The Santa Ana, Calif.-based company says the first impact on its technology will be on primary batteries, where new cathode materials will triple the power delivery of zinc air batteries.

The recently awarded U.S. Patent No. 7,282,167, “Method and Apparatus for Forming Nanoparticles,” covers QuantumSphere’s QSI-NanoGas Phase Condensation (GPC) process of manufacturing nano metals and alloys. According to the company, the QSI-Nano GPC process, allows for volume production of highly active catalyst materials that improve electrode performance in batteries, fuel cells, and on-board production of hydrogen through electrolysis for plug-in hybrid vehicles.

The company describes its manufacturing process as automated, scalable, and environmentally safe. Moreover, the process is said to be the first in the industry to make ultrapure, highly uniform and narrow-sized distribution particles without the use or production of hazardous chemicals or gasses (see the figure).

“In our experience, other methods for making nanomaterials to such exacting measurements proved too costly, too labor intensive, too inconsistent or unsafe,” said Kevin Maloney, president, CEO and co-founder of QuantumSphere. “The key to our company’s patented process is the ability to make commercial volumes of nano metals and alloys in a fully automated and scalable manner while maintaining size and purity.”

“This manufacturing process has been perfected over five years to the point where it now yields several kilograms of materials per reactor, per day, in a manner that is safe to employees and the environment,” says Maloney. “This ability enables us to supply multiple mainstream industries with nano metals and alloys at low cost. The QSI-Nano GPC process will be instrumental in fulfilling our company’s vision of enabling cleaner renewable energy sources for our future.”

The QSI-Nano GPC process is computer controlled and fully automated which allows continuous production of high quality materials and enables a significant reduction in costs for the production of QSI-Nanoiron, silver, copper, nickel, cobalt, manganese, and other nano metals and alloys. The company will bring three additional reactors online in January 2008, with a total production capacity of more than 500 kg per month.

Improving Zinc-Air Batteries

Using its nano materials, the company has designed a new cathode material for zinc air batteries such as the button cells used in hearing aids. When compared with a typical zinc-air cathode, the QSI-Nano Zinc-Air Cathode delivers a 320% increase in power delivery. When compared with alkaline cells, the QSI-Nano Zinc-Air Cathode offers about five times greater energy density, while maintaining similar costs.

The table below provides technical specifications for a “hypothetical” zinc air primary cell intended for applications with an average current draw of 0.8 A to 1.2 A continuous with pulses up to 5 A for 1 msec. Specifications for this cell are compared against an AA- alkaline cell.

Although the cell design in the table is described as hypothetical, the data shown is based on real dimensional and performance data. The physical model for the zinc air cell is Electric Fuel’s CB-29 cell, which is no longer in production. The performance of the zinc-air nano-cell is modeled from experimental batteries produced in the DoppStein Enterprises Laboratory and scaled to the CB-29 dimensions. The catalyst in the hypothetical cell is a nano powder produced by QuantumSphere and while the values shown are hypothetical, they are achievable according to the vendor.

Table. Hypothetical, zinc-air nano-cell vs. AA alkaline cell

Parameter

nano-Cell

AA alkaline cell

Weight (g)

15.9

24.2

Volume (cc)

5.3

7.5

Capacity at 0.50 A (Ah)

4.00

1.40

Open Circuit Voltage (V)

1.40

1.50

Ave. Voltage (V) at 0.25 A

1.22

1.15

Ave. Voltage (V) at 0.5 A

1.17

1.01

Rated Current (A)

up to 1.1

up to 1

Temperature range (ºC)

-20 to +60

-20 to +54

1-kHz Impedance (Ω), 50% depth of discharge

0.07

0.13

Energy (Wh) at 0.5 A

4.7

1.4

Specific Energy (Wh/kg) at 0.5 A

294

58

Energy Density (Wh/l) at 0.5 A

883

186

The new cathode material—because of its lighter weight and smaller volume—will enable the development of zinc air batteries in larger form factors, according to the company. One application for such batteries may be in recharging the Li-ion cells used in cell phones, digital still cameras, and other devices. For more information, visit www.qsinano.com.

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