FrogHeart

It’s Friday, April 13, 2012 and I wanted a little fun in my headline so Zhi Li and his colleagues in the Mitlin Group at the University of Alberta are not walking on eggshells. They are, instead, carbonizing them as a means of increasing the amount of electrical energy that can be stored as Michael Berger explains in his April 12, 2012 article, Converting eggshell membranes into a high-performance electrode material for supercapacitors (links have been removed from the following excerpt),

Today’s commercial supercapacitors – which are mostly electric double layer capacitors (EDLC) – store energy in two closely spaced layers with opposing charges and offer fast charge/discharge rates and the ability to sustain millions of cycles. Researchers have come up with various electrode materials to improve the performance of supercapacitors, focussing mostly on porous carbon due to its high surface areas, tunable structures, good conductivities, and low cost. In recent years, this has increasingly included research on various carbon nanomaterials such as carbon nanotubes, carbon nano-onions, or graphene.

“An ideal supercapacitor is one with both high energy density and high power density,” Zhi Li, a post doc researcher in David Mitlin’s group at the University of Alberta, explains to Nanowerk. …

…

In new work recently published in Advanced Energy Materials (“Carbonized Chicken Eggshell Membranes with 3D Architectures as High-Performance Electrode Materials for Supercapacitors”), first-authored by Li, researchers have demonstrated that a common daily waste – the eggshell membrane – can be converted into a high-performance carbon material for supercapacitors.

“Considering over 1000 billion eggs are consumed per year globally, and that 30–40 mg finished carbon is derivable from one egg, the eggshell membrane is indeed a reliable and sustainable resource for clean energy storage,” says Li.

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“The most exciting finding, for me, is that the amazing nature-made architecture of chicken eggshell membrane is critical to its performance as electrode materials after carbonization,” notes Li. “Why? The carbonized eggshell membrane is a real ‘integrated system’ composed of interwoven carbon fibers with diameter from 50 nm to 2 µm where the big fibers and tiny fibers are naturally connected together.”

As a consequence of their architecture,

… carbonized eggshell membrane can work at high current loading. That means capacitors based on it can be charged and discharged faster than capacitor based on traditional carbons.

You can find out more about the Mitlin Group here and you can find the article, “Carbonized Chicken Eggshell Membranes with 3D Architectures as High-Performance Electrode Materials for Supercapacitors,” here but it is behind a paywall. By the way, Dr. David Mitlin, group leader, is also a principal investigator at Canada’s National Institute of Technology.