Climate change is a problem for us. And the gas emitted from our cars and factories is one of the major causes . However, although it is a country that is largely involved in the problem, the United States decide pull out from Paris Climate Agreement and to leave . If so, can we use Exhaust Gas for something useful?
Scientists at Pennsylvania State University are thinking about converting carbon dioxide into electricity through fuel cells. There was a similar attempt before, but the initial result was very costly and were almost unable to produce electricity. However, in this experiment, the production volume per unit was 200 times higher than before . Still it is not enough yet. Nonetheless, these batteries can not save the environmental crisis, but in the short term it may be possible to reduce emissions to the atmosphere by reusing some of the exhaust gas.
This battery works by creating a pH gradient with two different pH values (hydrogen ion exponent) different liquids . On the other hand, air is mixed with sodium bicarbonate aqueous solution, and the other is mixed with carbon dioxide in aqueous solution. This causes a difference in pH value, and the positive charge amount becomes higher on the side where carbon dioxide is mixed. Two of the aqueous solution is manganese oxide of the electrode is sandwiched, for electrons to move to a more positive charge amount of high carbon dioxide side electrode by pH gradient between the aqueous solution, then current is generated. Once you have finished the process making electricity, you can make electricity by changing the aqueous solution . These research results were published by Environmental Science and Technology Letters .
However, in order integrate these batteries to our iPhone, still have a lot of challenges. Currently, the power density of this battery is very small . Roughly speaking, it is about 1 watt per square meter . For fuel cell technology with similar output, there are also research to generate electricity by using the water of the sea and river. With this one square meter battery, you can produce electricity less than one AA battery even if you activate for one hour . In addition, this experiment uses pure carbon dioxide instead of exhaust gas . In other words, in order to make electricity with gas discharged from a car or electric power plant, it is costly to refine the gas.
In the future this research may be the best way to make electricity from cheap carbon dioxide and conversely the electricity that can be produced against the electricity consumed to make a battery is too small and time and money It may be wasteful. But, the exhaust gas not only toss out to the atmosphere, it enabled the re-use and us to think.
