Assoc.Prof.Dr. Levent PARALI
Electrical Electronics Engineering

Pyroelectric nanogenerator charges Li-ion battery with harvested energy

Pyroelectric nanogenerator charges Li-ion battery with harvested energy

The scientists, Ya Yang and Sihong Wang from the Georgia Institute of Technology in Atlanta, Yan Zhang from the Georgia Institute of Technology and the Chinese Academy of Sciences in Beijing, and Zhong Lin Wang from both institutions, have published a paper on a pyroelectric nanogenerator in a recent issue of Nano Letters.

The scientists call the device a pyroelectric nanogenerator (PENG) because it's based on the pyroelectric effect, in which an anisotropic material's polarization changes in response to temperature fluctuations, which can be used to harvest thermal energy.

Unlike the Seebeck effect, which is used to harvest thermal energy based on the temperature difference between two ends of a device, the pyroelectric effect occurs in environments where the temperature is spatially uniform but changes over time. "Wasted heat is a rich source of energy that can be harvested,

" Zhong Lin Wang told Phys.org. "In 2010, for example, more than 50 percent of the energy generated from all sources in the US was lost mainly in the form of wasted heat, which presents us with a great opportunity to harvest this type of energy using nanotechnology. Harvesting thermoelectric energy mainly relies on the Seebeck effect, which utilizes a temperature difference between two ends of the device for driving the diffusion of charge carriers.

The presence of a temperature gradient is a must for the conventional thermoelectric cell. However, in an environment where the temperature is spatially uniform without a gradient, such as the outdoors in our daily life, the Seebeck effect is hardly useful for harvesting thermal energy arising from a time-dependent temperature fluctuation. In this case, the pyroelectric effect is the choice, which is about the spontaneous polarization in certain anisotropic solids as a result of temperature fluctuation, but there are few studies about using the pyroelectric effect for harvesting thermal energy.

 

" Read more at: http://phys.org/news/2012-11-pyroelectric-nanogenerator-li-ion-battery-harvested.html#jCp