Energy Harvesting Device Captures Power From Liquid Molecules To Generate Electricity on the Nanoscale

Advancements in technology have opened up new opportunities in generating electricity on the nanoscale. In a recent study, experts are exploring the potential of molecular power in revolutionizing energy production.

Molecular Thermal Motion

Energy is a necessity for human civilization. No matter where the energy comes form, people still find it most convenient to use electricity. At present, electrical energy is obtained by external energy such as wind energy, solar energy, hydroelectric energy, and others.

Molecular thermal motion refers to a special kind of dynamic motion which is different from ordinary mechanical motion. It is part of the internal energy of the physical system where the molecules of all substances are in constant and random movement above absolute zero temperature.

The Brownian motion of particles is an example of phenomenon caused by the movement of the surrounding liquid or gaseous molecules. Molecular thermal motion contains an enormous amount of energy like in an ideal gas where the average kinetic energy of thermal motion per mole of gas molecules at room temperature is 3.7 kJ.

It has been proven that wave energy technology can be a source of power generation. In every molecule of liquid on Earth, there is inherent power even if the liquid is at rest. There is a huge amount of air and liquid on Earth, and at the molecular level, the atoms and ions are constantly moving. If this nanoscale motion can be harvested, it has the potential to be a large source of energy. However, experts find it hard to utilize the energy of the liquid molecular thermal motion as an energy source due to the challenge in developing a viable device that can convert this energy to electricity.

Harnessing Molecular Power

A team of researchers led by Yucheng Luan tested a molecular energy harvesting device which can capture the energy from the natural movements of molecules in a liquid. Their findings revealed that it is possible to use molecular motion in generating a stable electric current.

In creating the device, Luan and his colleagues submerged nanoarrays of piezoelectric material in liquid. This allowed the movement of the liquid to move the strands like seaweed that wave in the ocean. In this case, the motion is on the invisible, molecular scale and the strands are composed of zinc oxide.

The researchers chose zinc oxide due to its piezoelectric properties where electric potential is generated when it bends, waves, or deforms under motion. As a well-studied piezoelectric material, zinc oxide can be easily synthesized into different nanostructures such as nanowhiskers. Nanowhiskers refer to a neat and orderly structure of many nanowires which are similar to the bristles on a toothbrush.

The energy harvester developed by the team can be used in powering nanotechnologies such as implantable medical devices. They can also be scaled to full-size generators and kilowatt-scale energy production. A key design feature of this device is its independence from external forces which increases its potential as a revolution in clean energy source.

Molecular thermal motion harvester devices do not require any external stimulation. According to Luan, this potential is a big advantage compared with other energy harvesters.