A research team at DGIST has developed a wearable device that harvests electrical energy using only body movements. This three-dimensional stretchable piezoelectric energy harvester attaches to the skin or clothes, and the produced energy can power electronic devices.
Generally, energy harvesters are of two types: one that works on the Triboelectric effect and the other on the piezoelectric effect. The triboelectric effect is an electrification in which certain materials, when rubbed together, become electrically charged. Meanwhile, the piezoelectric effect generates electric charge when mechanical stress is applied.
The developed device works on the piezoelectric effect, generating electricity from physical activities like joint movements. Though several studies have focused on piezoelectric energy harvesters, most use organic or composite-based piezoelectric materials. Such devices have proven inefficient in harvesting energy from body movements, ultimately restricting their use in wearable devices.
To overcome these limitations, the team led by Prof. Jang Kyung-In uses lead zirconate titanate, a material with a high piezoelectric efficiency. Though quite efficient, it is hard and brittle, making it difficult to embed in stretchable devices.
Therefore, experimenters designed PZT into a deformation-insensitive three-dimensional structure that ensures high energy efficiency and stretchability. The team also introduced a new curvature-specific coupling electrode design. This design divides the electrodes into sections to ensure the electricity is not canceled.
Electric textile lights a lamp when stretched
The given changes made a highly efficient stretchable piezoelectric energy harvester, which could soon be commercialized. This energy collector is 280 times more competent than conventional energy harvesters.
“Developing this highly efficient stretchable piezoelectric energy harvester technology is a major achievement of this research. We expect this technology to become useful after commercialization and lead to the practical use of wearable energy harvesters,” said Prof. Jang.
Journal Reference:
- Junwoo Yea, Jeongdae Ha, Kyung Seob Lim, Hyeokjun Lee, Saehyuck Oh, Janghwan Jekal, Tae Sang Yu, Han Hee Jung, Jang-Ung Park, Taeyoon Lee, Jae-Woong Jeong, Hoe Joon Kim, Hohyun Keum, Yoon Kyeung Lee, and Kyung-In Jang. Curvature-Specific Coupling Electrodes Design for Stretchable Three-dimensional Inorganic Piezoelectric Nanogenerator. ACS NANO. DOI: 10.1021/acsnano.4c09933
