One of the most expensive components of a battery is often the cathode, if its made of cobalt or precious metal. Swedish scientists may have discovered a way to replace pricy metal cathodes with a goopy byproduct of paper processing known as "brown liquor".

That is the result of the sulfite process for producing wood pulp. The brown sludge is a mix of spent chemicals, lignin and hemicellulose, gathered from a process where its extracted from wood chips bathed in sulfurous acid in pressure vessels. It is burned to generate steam in the paper mill. It also makes good low cost cathodes as well.

Olle Inganas, Professor of Biomolecular and Organic Electronics at Linköping University in Sweden, and Grzegorz Milczarek, a researcher at Poznań University of Technology in Poland made discovery which was published today in the journal Science.

"Nature solved the problem long ago," Inganas is quoted in a University article. The photosynthetic process is the inspiration for the discovery. It is primarily broken down lignin, part of the cell wall, and lignin can be further broken down into quizones, electrically conductive molecules that transport electrons during photosynthesis.

The research team created an inexpensive cathode with quizones carrying electrons across the semi permeable membrane capable of holding a charge. At current, the prototype continually discharges when idle, and running down in a matter of hours.

[LIU via Discovery via TreeHugger]