Making batteries from seafood leftovers.

Hakai magazine explains how we can turn crab and lobster shells into batteries, plastics and (maybe) scaffolds for growing new organs:

[Mark] MacLachlan [of the University of British Columbia in Vancouver] is after one particular component of the material that makes up the shells—chitin, a tough substance that is structurally similar to the cellulose in plant cell walls. The chitin is made of rod-shaped nanocrystals that are organized in a helix. Their orientation reflects light in a way that makes the shells iridescent.

From this starting point, MacLachlan has figured out how to transform chitin into a number of useful materials, such as an iridescent film that changes color when pressure is applied, and a litmus paper-like film that detects different chemicals in water.

But one of the most promising materials begins when the chitin is cooked at 900 °C in a nitrogen atmosphere. This transforms it into a nitrogen-doped carbon that can be used to make electrodes for batteries. “Chitin-based films are very porous, so they have a large surface area,” says MacLachlan. This gives them a high capacity for storing charge.

But other options, such as chitin-based bioplastics, have great potential.

Biomaterials based on chitin or cellulose could form scaffolds to help support the growth of new tissues in the body, then dissolve once they are no longer needed.

[via Mr. Lloyd]