Nanotechnology as a Megatrend and a Case Study of Nanophosphate Li-Ion Batteries: Technology Leadership Brief
Published October 8, 2012 by SAE International in United States
Annotation of this paper is available
Event: SAE Convergence 2012
Nanotechnology pertains to materials, components or devices with a scale of features on the order of 1 to 100 nanometers. While that definition might seem to be fairly specific, there is actually abroad-based and far reaching amount of research and development occurring globally at this scale, which is just above that of individual atoms.
Considering that the context of this briefing is automotive applications, we will exclude the segments of nanotechnology dealing with biology or molecular engineering in order to focus on nanoscale materials science. Even with this reduction of scope, there is still a broad range of technologies to be considered. Automotive advances ranging from lighter and stronger structural materials to more efficient powertrains and advanced electronics can all be significantly advanced by nanotechnology.
Since it is not possible to discuss a comprehensive list of applications in just a few pages, it is best to illustrate the megatrend of nanotechnology through a few specific examples. We begin with an automotive application that is easy to visualize: lubricant additives.
With the ability to produce nanoscale spherical particles, it is possible to augment the properties of engine oil by adding the functional equivalent of millions of ball bearings between a cylinder and its cylinder wall. Because nano-particles are so small and light, they remain suspended in the oil and provide a rolling mechanism to further reduce friction beyond the ordinary shearing of the oil. It should be mentioned that the nano-particles are so small that the same particle does not touch the cylinder and the cylinder wall but there is actually a series of rolling elements that fit between these two surfaces in an ordinary engine.
While the mechanical benefits of extremely small particles are easy to imagine, many of the more profound advances enabled by nanotechnology come from a fundamental difference in performance capabilities. For example, nano-materials have remarkably high surface areas, often exceeding 500 m2/g, which is about the area of a basketball court for a single gram of material! Because chemical reactions are often affected by surface area of the reactants, nanotechnology represents a significant opportunity to dramatically accelerate such reactions (or reduce the size/weight of associated automotive components).
One example application that can benefit from an order of magnitude more surface area is the catalytic converter in a typical exhaust system. As the exhaust gases flow through the converter, a nano-structured catalyst is able to simultaneously react with many more pollutants thereby improving the effectiveness of the system, even if it contains a lower volume of the very expensive catalyst material.
Similarly, lithium-ion batteries are another field where the surface area increases of a nano-structured material offer significant performance advantages. A123 Systems has successfully commercialized a nano-structured lithium-ion battery material named Nanophosphate® and the balance of this technology brief provides a case study on nanotechnology's importance to this application.