Canadian research team reports major breakthrough in lithium battery technology

The research team of professor Linda Nazar, graduate student David Xiulei Ji and postdoctoral fellow Kyu Tae Lee are one of the first to demonstrate robust electrochemical performance for a lithium-sulphur battery. The finding is reported today in the on-line issue of Nature Materials.

The prospect of lithium-sulphur batteries has tantalized chemists for two decades, and not just because successfully combining the two chemistries delivers much higher energy densities. Sulphur is cheaper than many other materials currently used in lithium batteries.

It has always showed great promise as the ideal partner for a safe, low cost, long lasting rechargeable battery, exactly the kind of battery needed for energy storage and transportation in a low carbon emission energy economy.

“The difficult challenge was always the cathode, the part of the battery that stores and releases electrons in the charge and recharge cycles,” said Dr. Nazar. “To enable a reversible electrochemical reaction at high current rates, the electrically-active sulphur needs to remain in the most intimate contact with a conductor, such as carbon.”

The Canadian research team leap-frogged the performance of other carbon-sulphur combinations by tackling the contact issue at the nanoscale level. Although they say the same approach could be used with other materials, for their proof of concept study they chose a member of a highly structured and porous carbon family called mesoporous carbon. At the nanoscale level, this type of carbon has a very uniform pore diameter and pore volume.

Using a nanocasting method, the team assembled a structure of 6.5 nanometre thick carbon rods separated by empty three to four nanometre wide channels. Carbon microfibres spanning the empty channels kept the voids open and prevented collapse of the architecture.

Filling the tiny voids proved simple. Sulphur was heated and melted. Once in contact with the carbon, it was drawn or imbibed into the channels by capillary forces, where it solidified and shrunk to form sulphur nanofibres. Scanning electron microscope sections revealed that all the spaces were uniformly filled with sulphur, exposing an enormous surface area of the active element to carbon and driving the exceptional test results of the new battery.

“This composite material can supply up to nearly 80 percent of the theoretical capacity of sulphur, which is three times the energy density of lithium transition metal oxide cathodes, at reasonable rates with good cycling stability,” said Dr. Nazar.

What is more, the researchers say, the high capacity of the carbon to incorporate active material opens the door for similar “imbibed” composites that could have applications in many areas of materials science.

The research team continues to study the material to work out remaining challenges and refine the cathode's architecture and performance.

Dr. Nazar said a patent has been filed, and she is reviewing options for commercialization and practical applications.

Contact:

Linda Nazar, Canada Research Chair, University of Waterloo
519-888-4567, ext. 84637 or lfnazar@uwaterloo.ca
NSERC contact:
Arnet Sheppard, 613-995-5997 or arnet.sheppard@nserc-crsng.gc.ca

Media Contact

Linda Nazar EurekAlert!

All latest news from the category: Power and Electrical Engineering

This topic covers issues related to energy generation, conversion, transportation and consumption and how the industry is addressing the challenge of energy efficiency in general.

innovations-report provides in-depth and informative reports and articles on subjects ranging from wind energy, fuel cell technology, solar energy, geothermal energy, petroleum, gas, nuclear engineering, alternative energy and energy efficiency to fusion, hydrogen and superconductor technologies.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors