Rice husks recycled into battery parts

Researchers have devised a way to recycle rice husks into lithium battery electrodes, according to a study in Proceedings of the National Academy of Sciences.

Farmers grow 422 million metric tons of rice per year in roughly 75 countries around the world. Each rice kernel is shielded from pests and germs by a silica-containing husk. People have used the husks in fertilizer, but the study authors wanted to investigate more high-tech applications.

The team analyzed rice husks from a crop grown in Daejeon in the Republic of Korea. The outer husk had ridges, and most of the silica was located at the edges. By treating the husks with acid and heating them, the researchers extracted 99.92 percent pure silica. The silica was then converted into silicon and tested as a battery component.

The silicon “exhibits excellent electrochemical performance as a lithium battery anode,” the team writes. The results “show how a part of the waste from one of the most popular crops, rice husks, can be a resource that helps meet the ever-increasing demand for Si in advanced batteries.” Roberta Kwok | 8 July 2013

Source: Jung, D.S. et al. 2013. Recycling rice husks for high-capacity lithium battery anodes. Proceedings of the National Academy of Sciences doi: 10.1073/pnas.1305025110.

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