October 21, 2021
  • October 21, 2021

The film generates electricity from mechanical movement

By on October 4, 2021 0

Advances towards low power consumption and energy efficient devices are hotly targeted by electronics industries. The transformation to low wattage LED lighting is a prime example of this trend. Another option is the development of energy recovery and self-sufficient devices.

(Clockwise from bottom right): Researchers Manisha Sahu, Sugato Hajra, Kyungtaek Lee, and Professor Hoe Joon Kim, who have developed a composite film that can be used in recovery generators in ‘energy. Image credit: Daegu Gyeongbuk Institute of Science and Technology.

The goal is to use materials capable of displaying piezoelectric and triboelectric effects to convert mechanical energy into electrical energy. Under mechanical stress, piezoelectric materials produce an electrical charge; Meanwhile, the triboelectric effect is the accumulation of charges on two different materials, after mutual contact.

Piezoelectric Nanogenerators (PENGs), Triboelectric Nanogenerators (TENGs) and even Hybrid Piezo-Triboelectric Energy Harvesters (HNGs) which have enhanced energy harvesting capabilities have been developed to power low-power electronics through a simple movement.

These devices generally need dielectric materials that can retain their polarization and multiferroic materials with ferromagnetic properties suitable for this task.

The study was published in the journal Nano energy.

Collaborative research carried out by researchers from Daegu Gyeongbuk Institute of Science and Technology (DGIST), Korea and the Indian Institute of Technology, Guwahati, India, has led to a composite film with potential application in combination with other materials to make energy recovery generators.

A cost effective method was used to design the composite film, where a multiferroic material, bismuth titanate Bi4Ti3O12 (or BiTO), was introduced into a flexible triboelectric polymer (PDMS).

Our main motivation behind this work was to develop a room temperature multiferroic material with colossal high permittivity for a hybrid piezo-triboelectric energy recuperator..

Hoe Joon Kim, Study Leader and Professor, Daegu Gyeongbuk Institute of Science and Technology

The researchers sandwiched the BiTO-PDMS between the aluminum layers to make an HNG that can generate an electrical charge when squeezed and released.

The reason for the generation of current by these multiple layers lies in the characteristics of the film and its response to mechanical action. The layers serve as electrodes, and when the device is squeezed and released, the piezoelectric and triboelectric nature of the film synergizes to produce charges on the electrodes, which creates a voltage.

The synergistic effect improves energy recovery performance. With the use of multiple HNGs, researchers were able to build a multi-unit HNG with the potential to power a wristwatch and a calculator.

For the first time, single-phase room temperature multiferroic material with colossal dielectric constant has been achieved. The internal polarization amplification of the polymer has been improved, increasing the energy harvesting performance of the hybrid energy recuperator.

Hoe Joon Kim, Study Leader and Professor, Daegu Gyeongbuk Institute of Science and Technology

As work progresses to improvise the energy harvesting performance of nanogenerators, the tiny devices can create the potential to invalidate batteries in several cases, making electronics more suitable and more self-sufficient.

Journal reference:

Hajra, S., et al. (2021) Bismuth Titanate-PDMS Lead-Free Flexible Composites: A colossal multifunctional dielectric material for hybrid piezo-triboelectric nanogenerator to sustainably power portable electronics. Nano energy. doi.org/10.1016/j.nanoen.2021.106316.

Source: https://www.dgist.ac.kr/en/

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