Cellulose nanocrystals and supercapacitors at McMaster University (Canada)

Photos: Xuan Yang and Kevin Yager.

Photos: Xuan Yang and Kevin Yager. Courtesy McMaster University

I love that featherlike structure holding up a tiny block of something while balanced on what appears to be a series of medallions. What it has to do with supercapacitors (energy storage) and cellulose nanocrystals is a mystery but that’s one of the images you’ll find illustrating an Oct. 7, 2015 news item on Nanotechnology Now featuring research at McMaster University,

McMaster Engineering researchers Emily Cranston and Igor Zhitomirsky are turning trees into energy storage devices capable of powering everything from a smart watch to a hybrid car.

The scientists are using cellulose, an organic compound found in plants, bacteria, algae and trees, to build more efficient and longer-lasting energy storage devices or supercapacitors. This development paves the way toward the production of lightweight, flexible, and high-power electronics, such as wearable devices, portable power supplies and hybrid and electric vehicles.

A Sept. 10, 2015 McMaster University news release, which originated the news item, describes the research in more detail,

Cellulose offers the advantages of high strength and flexibility for many advanced applications; of particular interest are nanocellulose-based materials. The work by Cranston, an assistant chemical engineering professor, and Zhitomirsky, a materials science and engineering professor, demonstrates an improved three-dimensional energy storage device constructed by trapping functional nanoparticles within the walls of a nanocellulose foam.

The foam is made in a simplified and fast one-step process. The type of nanocellulose used is called cellulose nanocrystals and looks like uncooked long-grain rice but with nanometer-dimensions. In these new devices, the ‘rice grains’ have been glued together at random points forming a mesh-like structure with lots of open space, hence the extremely lightweight nature of the material. This can be used to produce more sustainable capacitor devices with higher power density and faster charging abilities compared to rechargeable batteries.

Lightweight and high-power density capacitors are of particular interest for the development of hybrid and electric vehicles. The fast-charging devices allow for significant energy saving, because they can accumulate energy during braking and release it during acceleration.

For anyone interested in a more detailed description of supercapacitors, there’s my favourite one which involves Captain America’s shield along with some serious science in my April 28, 2014 posting.

Getting back to the research at McMaster, here’s a link to and a citation for the paper,

Cellulose Nanocrystal Aerogels as Universal 3D Lightweight Substrates for Supercapacitor Materials by Xuan Yang, Kaiyuan Shi, Igor Zhitomirsky, and Emily D. Cranston. Advanced Materials DOI: 10.1002/adma.201502284View/save citation First published online 2 September 2015

This paper is behind a paywall.

One final bit, cellulose nanocrystals (CNC) are sometimes referred to as nanocrystalline cellulose (NCC).

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