Rice-husks could build better batteries
Lithium ion batteries are used in everything from cellphones to hybrid cars, so improving their function can have far-reaching benefits. Most lithium ion batteries use electrodes made from graphite, but there's been ongoing interest in switching to silicon electrodes, because it holds a much higher charge. However, there's a trade-off, as silicon electrodes degrade much more quickly. This problem is called "capacity fade."
Researchers in South Korea are looking at how silicon made from rice-husks may offer a solution to this problem. New Scientist reports:
"To find out, Choi's team chemically converted the rice husk silica – or silicon dioxide – into pure silicon and then fashioned battery electrodes out of the material. It showed no capacity fade even after 200 charge-drain cycles. A synthetic silicon electrode used for comparison had a higher initial charge capacity but faded badly: it began performing worse than the rice-husk electrode after 10 to 15 cycles."
Although the process begins with a biodegradable material, converting the silica is still an energy intensive process. Read the full story here.