VOA慢速英语2014 烟头转变成电池（在线收听）

Turning Cigarette Butts to Batteries 烟头转变成电池

If you see a person carelessly throw a cigarette to the ground, what are you likely to think?

That depends.

If you hate people throwing things on the ground, you might think, “That person should not litter.” If you are a smoker, you might think, “I would sure like a cigarette right now.”

Most likely, though, you are not thinking, “You know, that unused cigarette butt could be used to make something, something amazing!” 

That is, unless you are a creative scientist. If you are, you may see potential -- a possibility -- where others simply see trash.  That is just what has happened in South Korea. 

The spirit of invention can hit at the strangest times and in the most unusual places. In South Korea, it happened near a trash can. 

Kim Gil-Pyo is with the Seoul National University. Mr. Kim says he saw people throwing away cigarette butts. And that got him thinking. He began wondering if something useful could be made from them.

The result? Mr. Kim and other researchers found a way to turn, or convert, cigarette butts into the materials required for high-performance batteries.

We often say, “One person’s trash is another person’s treasure.” And in this example, that is unquestionably true.             

The Parts of a Cigarette

Kim Gil-Pyo says he and his fellow researchers looked closely at used cigarette filters. The filter is the part of the cigarette that smokers put into their mouths. Filters are made of a material called “cellulose acetate.”

Mr. Kim explains that cellulose acetate can be made into another material: carbon. He says the pieces of cellulose acetate, known as fibers, are changed through a one-step burning process. After this, he says, they are converted, or turned into, an energy storage material.

But why use carbon? Carbon has many qualities that seem to make it the perfect material. Carbon has a high surface area. It conducts electricity well. In other words, carbon can easily carry an electrical current. It also stays stable, unlikely to change, for a long time. And carbon does not cost a lot. All these qualities make it the most popular material for making super-capacitors. 

Super-capacitors are good at storing energy. They have high-power mass, or density. They require only a short time for re-charging. And they have a long lifecycle. Super-capacitors are used in products such as laptop computers and cell phones. They are also used in industrial energy converters, like wind turbine machines. 

Combining carbon and super-capacitors seems like a perfect marriage.

Kim Gil-Pyo tells the Reuters News Agency that cigarette butts could affect the economy is a huge way. They could prove to be a low-cost source of carbon material. They are so cheap that smokers throw them to the ground. And you don’t get much cheaper than that. 

Seoul National University professor Yi Jong-heop led this research. The findings were published last month in the journal Nanotechnology.