Imagine a world where pacemakers never need new batteries and a walk through a park keeps your mp3 player at full charge. Dr. Yong Shi, Assistant Professor of Mechanical Engineering at Stevens Institute of Technology, is developing the technology to make those dreams a reality.
Dr. Shi's patented piezoelectric (PZT) nanofibers are being put to use converting mechanical energy generated by the human body into electricity that can power everything from iPods to nanobots. Piezoelectricity, meaning literally electricity produced by a "squeeze," has sweeping potential as new sources of power are sought for the small but energy-hungry devices proliferating in our society. PZT nanogenerators can also function as minute power plants in biomedical devices such as pacemakers or nanodevices carried in the bloodstream. Using converted mechanical energy generated simply by movement and pressure in the blood, these nanogenerators can power devices without reliance on batteries.
Dr. Shi gives sneak peeks of his PZT technologies to students in his 600-level nanotechnology courses at Stevens, sharing the latest on his lab experiments in the occasional lecture. Now, Dr. Shi opens the door to the science through an interview that debuts lab video of the device at work.
Nanogenerator fabrication starts with constructing the PZT nanofibers through a combination of macro- and nano-processes. First, the nanofibers are deposited on silicon wafers and attached to electrodes fabricated at the macro level. The PZT nanofibers are then embedded into biocompatible polymers and released from the substrate, resulting in a flexible device that can be incorporated into many applications.
Although biomedical devices are a featured application of this technology, due to the small size at which it can function, there is an incredible range of possibilities for implementation. The flexible, durable generators could be embedded in shoes or clothing to produce electricity that powers handheld devices. In a fully-wired world where every object is a "smart" object, such battery-free power sources would be essential to the functioning of hundreds of millions of everyday items.
"The next step is further increasing efficiency through optimization of design and simplification of the fabrication process to scale up production," reports Dr. Shi.