Pulickel Ajayan Leads Team to Boost Lithium Battery Performance

Pulickel Ajayan

Pulickel Ajayan is leading a team that is working to boost lithium battery performance by creating hybrid carbon nanotubes. Pulickel Ajayan, an Indian American materials scientist said his team is growing nanotubes to look and act like the coaxial conducting lines used in cables. The coax tubes consist of a manganese oxide shell and a highly conductive nanotube core.

“It’s a nice bit of nanoscale engineering,” said Ajayan, Rice University professor in mechanical engineering and materials science. “We’ve put in two materials - the nanotube, which is highly electrically conducting and can also absorb lithium and the manganese oxide, which has very high capacity but poor electrical conductivity,” said Arava Leela Mohana Reddy, Rice postdoctoral researcher.

“But when you combine them, you get something interesting.” That would be the ability to hold a lot of juice and transmit it efficiently. The researchers expect the number of charge/discharge cycles such batteries can handle will be greatly enhanced, even with a larger capacity.

“Although the combination of these materials has been studied as a composite electrode by several research groups, it’s the coaxial cable design of these materials that offers improved performance as electrodes for lithium batteries,” said Ajayan.

“At this point, we’re trying to engineer and modify the structures to get the best performance,” said Manikoth Shaijumon, also a Rice postdoctoral candidate.

The hybrid nanocables grown in a Ricedeveloped process could also eliminate the need for binders, materials used in current batteries that hold the elements together but hinder their conductivity said a Rice release.

Ajayan’s research has been in the field of nanotechnology. He is noted for leading advances in carbon nanotube technology. In 1992, at the NEC Fundamental Research Laboratory in Tsukuba, Japan (the lab of Dr. Sumio Iijima, the discoverer of nanotubes), he teamed with Thomas Ebbesen to develop the first method for making macroscopic quantities of nanotubes. They demonstrated that nanotubes can be produced in bulk quantities by varying the arc-evaporation conditions. The experiment involved placing two graphite rods millimeters apart, and wiring them to a power supply. As 100 amperes of current sparked between the rods, hot plasma was created by the vaporization of carbon. Some of this plasma underwent condensation and formed nanotubes. This was a considerable advance in the technology, and created a boom in carbon nanotube research.

Professor Ajayan’s research interests are mainly focused on the synthesis and characterization of one-dimensional nanostructures with special emphasis on carbon nanotubes. He is a pioneer in the area of nanotubes and has published some of the key papers in the field with more than 3000 citations for his work in this area. Among his research accomplishments, he presented a simple chemical method of opening and filling nanotubes. He, along with Vinod P. Veedu, Anyuan Cao and Mehrdad N. Ghasemi Nejhad have been awarded a Guinness World Record for creating the smallest nanotube brushes with bristles. According to a Science Watch Analysis, he is the 7th most cited author in Nanotechnology for the period of 1992-2002.

Over the years, Ajayan has been involved in several of the initial works on nanotubes, in particular the large-scale synthesis of nanotubes and opening and filling of nanotubes. Ajayan’s research is focused on building functional architectures with carbon nanotubes, creating multi-functional nanocomposite materials and hybrid nanoscale biomaterial systems.

And while looking for the simple and the beautiful in science he’d rather not spend large chunks of time “writing research proposals to raise money, too much travel, and many unproductive meetings” that are part of the scientist’s role. “In the long run, I would like to create materials that are smart and responsive, more like biological systems; where structure and function have a symbiotic relationship. In the short term, I would like to build architectures with carbon nanotubes. If there was one material that I would hold up and say ‘This is it’ as far as nanotechnology is concerned, that is carbon nanotubes,” said Ajayan who has been on the faculty at Rennselaer since 1997. Professor Ajayan’s research interests are mainly focused on the synthesis of nanostructures, the study of their structure and properties in relation to size and confinement. He has demonstrated several possibilities for using these quasi one dimensional structures as templates and molds for fabricating nanowires, composites and novel ceramic fibers. Major goals of his research include producing macro assemblies made of nanostructures for applications, understanding growth mechanisms of nanostructures and designing new structures and multifunctional nanocomposites.

Ajayan’s early education was in Kerala, India. Till the sixth standard, he studied in a government school in Kodungallur, after which he moved to Loyola School, Thiruvananthapuram, a high school he has credited for making a strong impact on him and for making him “realize that learning is the most exciting thing one can ever befriend”. He graduated from Loyola in 1977. In 1985, Ajayan graduated with a B.Tech. degree in Metallurgical Engineering from the Institute of Technology, Banaras Hindu University.

He topped his class, thereby winning the department’s gold medal. In 1989, he earned a Ph.D in Materials Science and Engineering from Northwestern University, Evanston, Illinois. If he had not become a scientist, Pulickel M. Ajayan would perhaps have become a poet or a film director. That’s because as he once acknowledged, “I am always looking for simple and beautiful things in science, be it a process, a structure, or a model.”

BY AJAY GHOSH