Batteries, one of the most commonly used energy storage devices, find use across a broad spectrum of applications encompassing military, automotive, healthcare, and consumer electronics. Batteries are available in varying chemistries, have different features, and accordingly different applicability. In the recent years, research in lithium ion batteries has gained impetus with the increasing application of these batteries, particularly in the consumer electronics sector owing to their high-energy density. However, issues such as durability in manganese lithium ion batteries, low power density in iron phosphate lithium ion batteries, and thermal runaway in cobalt oxide lithium
ion batteries plague these batteries. Research is ongoing to address these challenges and enable batteries with superior features.

The US-based Altair Nanotechnologies Inc. has developed battery electrode materials that bring about a three-fold increase in the power observed in the existing lithium ion batteries. In addition to having the advantage of recharge times measured in a few minutes rather than hours, these batteries would cost the same as lithium ion batteries available in the market. Most rechargeable lithium ion batteries currently used employ graphite as the negative electrode material. Cobalt oxide is used for the positive electrode with a lithium salt dissolved in an organic solvent as an electrolyte. The properties of these electrode materials play a significant role in the charge rate of the battery. Altair has used its patented nanotitanate material instead of graphite as the negative electrode material in the new NanoSafe batteries.

The developed nanomaterial possesses an almost zero strain crystal lattice capable of preventing battery electrode material fatigue that is responsible for limited battery life. It also increases the number of recharge and discharge cycles from a few hundreds to several thousands, preventing lithium metal plating as the electrochemical properties of nanotitanate permit deposition of lithium in the particles at high rates. As there is no undesirable interaction with the electrolyte in this battery, rapid charging is a possibility. Altair claims that in a recent laboratory testing, the NanoSafe cell was found capable of being charged to almost 80% charge capacity within a minute, although the charge rates vary depending on the application environment. Additionally, increased battery discharge rates can be achieved, which are important in applications requiring bursts of power such as a freeway electric vehicle under rapid acceleration. The NanoSafe battery enables the delivery of high-power surges without thermal runaway issues or performance damages to the battery.

Lithium ion batteries usually experience a loss in capacity with increased temperatures and do not perform well at cold temperatures. The new electrode materials developed by Altair aids in the creation of high-temperature stability that facilitates the battery to perform in warm environments (temperature range of 55 degrees C to 65 degrees C), at the same time maintaining beneficial features such as longevity and robustness. The batteries are also functional in cold conditions of -30 degrees C temperature.

"We conduct all the international tests for safety. We have passed these tests so far. Altairnano is working with an organization that defines the standards and requirements for nanotechnology safety. While making the battery materials, for making naocrystallides we actually pour the nanocrystallides in the spherical shape which is 10 micrometers in diameter. This is no longer nanotechnology,
and hence the materials can be handled freely without any nanoparticle contamination. Each individual crystallide is nanosized, but as they are bound and contained in a spherical structure they are very easy to handle," Robert Pedraza, vice president of strategy and business development tells Technical Insights.

Lithium ion batteries developed using Altair electrode materials are to compete with lead acid batteries for telecom, uninterrupted power supply (UPS), and stationary applications. Lead acid batteries require high maintenance and the advantages of lithium ion batteries--such as robustness, reliability, and long life, coupled with less maintenance--would make them an economic option. Another application domain with enormous potential for lithium ion batteries is the hybrid electric vehicles market. Currently, nickel metal hydride batteries are in use. Using very large, high-performance, safe lithium ion batteries would have a cost advantage owing to being lightweight and having long life. Potential applications of fast charging batteries will be hybrid electric vehicles, medical surgery tools, and portable electronics. They would also play a role in the handheld power tools market for enhancing the productivity of construction workers while reducing overhead costs. Altair has been granted two patents (on January 7th, 2005, and January 14th, 2005) and has received a grant from the National Science Foundation.

Details:

Robert Pedraza

Vice President -Strategy and Business Development,

Altair Nanotechnologies Inc.,

204 Edison Way, Reno,

NV 89502

Phone: 775-858-3702

Fax: 775-858-1619

E-mail: rpedraza@altairnano.com.

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