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Research Highlights, Development of a “Hygroelectric Cell” that Generates Electricity Using Changes in the Moisture in the Air

Department of Information Technology and Human Factors

Department of Electronics and Manufacturing

Development of a "Hygroelectric Cell" that
Generates Electricity Using Changes
in the Moisture in the Air

KOMAZAKI Yusuke
Sensing System Research Center and Human Augmentation Research Center

Released: June 2, 2021

Power generation using humidity changes in the air as an energy source

We developed a hygroelectric cell that generates power using moisture in the air. It operates on a new principle combining deliquescent material and osmotic power, and can continuously produce electric currents at the mA level due to low internal resistance. Since this element can generate power using the humidity difference between day and night by simply exposing it to air, it is expected to be used as an extremely low-power power source for things like IoT equipment.

The hygroelegtric cell that was developed (left) and the voltage of the hygroelectric cell when the humidity changes (right)

Self-contained energy harvesting in response to growing number of electronics

As the number of electronic devices continues to increase, this also increases the frequency to which people periodically charge and replace the batteries of these devices, which creates a labor burden to handle these tasks. Although development is being carried out for energy harvesting that uses tiny amounts of energy in the environment, the energy used by conventional technologies is not readily available in all areas, making it difficult to create technology that allows users to generate power anywhere.

Just leave it and it generates electricity

The hygroelectric cell that we developed combines the hygroscopic action of a deliquescent inorganic salt solution and osmotic power generation, enabling a current at the mA level to be produced using fluctuations in humidity. The hygroelectric cell consists of an open chamber and a closed chamber, both of which contain an electrolyte solution consisting of water and deliquescent lithium salt. The concentration of the electrolyte solution does not change in the closed chamber, but the concentration of the electrolyte solution in the open chamber changes depending on the humidity. Due to the concentration difference between the open chamber and the closed chamber, a voltage is generated between the electrodes. Humidity in the air fluctuates by several tens of percent during the day due to temperature changes during the day and night and other factors, so it can generate electricity anywhere by just leaving it where it is.

Improvement of output and durability

The technology can be described as a renewable energy source that utilizes slight humidity variations in the air. Since hygroelectric cells can be expected to be used as a power source for IoT equipment, we will conduct research to improve output and durability for practical applications.

Contact for inquiries related to this theme

Smart Sensing Research Team, Human Augmentation Research Center
and Flexible Device Implementation Team, Sensing System Research Center

KOMAZAKI Yusuke, Researcher

Social Innovation Building, Kashiwa II Campus, University of Tokyo, 6-2-3 Kashiwanoha, Kashiwa, Chiba 277-0882 Japan

E-mail: harc-liaison-ml*aist.go.jp (Please convert "*" to "@".)

Web: https://unit.aist.go.jp/harc/en/

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