Next Generation Battery Power – Nanogenerator

Battery power for handheld devices continues to attract novel and innovative methods. Last year, at the Rice Business Plan competition, the University of Arizona team showed off a technology that used piezoelectric crystal which they stimulated with an ultrasound wave to recharge the device’s battery. In concept it looked great, but in reality the transmitter had to be within about 18 inches of the device for it to work. Splashpower uses inductive coupling to recharge devices. You lay your portable devices on a pad and it recharges it for you without the need of plugs and cables. Inductive coupling works well at low power which is why it’s used to recharge electric toothbrushes and the like.

At the Rice Business Plan Competition this year, MIT, demonstrated the PowerPad which uses a non-radiative energy field to recharge devices. Essentially, energy at a particular frequency can cause objects to vibrate.

At the Idea2Product Competition held at the University of Texas, the winning team in 2005 was Micro Dynamo which developed a battery that could be recharged by human motion. It was designed with the military in mind. A soldier could recharge the battery as he walked. It uses ultra capacitors with a rare-earth magnet dynamo to capture human motion and then slowly recharge the battery which can hold the charge for a longer period of time.

Now comes, Nanogenerator, which uses the mechanical motion of nanolevel hairs to generate electricity. Zhong Lin Wang of Georgia Tech and his graduate students created zinc oxide nanowires and used an atomic force microscope tip to move the wires and thus create an electrical charge. Zinc oxide wires are piezoelectric and thus product direct current. By using mechanical motion to generate electricity, the researchers can scale the device to be almost any size and controlled by almost any moving force such as human motion, water movement, air flow, and more. Because it doesn’t require chemicals such as those found in batteries, it could also be used within the human body for powering biosensors.
The researchers built a prototype device and were able to produce 0.5 nanoamperes of current for more than an hour.

Best regards,
Hall T.