The biosupercapacitor, which features graphene layered with modified human proteins as an electrode, could be used in next-generation implantable devices to speed bone growth, promote healing or stimulate the brain.
Modern pacemakers are typically 6 to 8mm thick, with half of the volume occupied by the battery. The biosupercapacitor is 1µm thick, meaning it can bend and twist inside the body without any mechanical damage, while storing more charge than energy lithium film batteries of comparable size.
“Combining energy harvesters with supercapacitors can provide endless power for lifelong implantable devices that may never need to be replaced,” said UCLA researcher Maher El-Kady.
Although supercapacitors have not been widely used in medical devices, the study shows they may be viable for that purpose. “In order to be effective, battery-free pacemakers must have supercapacitors that can capture, store and transport energy, and commercial supercapacitors are too slow,” El-Kady said. “Our research focused on custom-designing a supercapacitor to capture energy effectively and finding a way to make it compatible with the human body.”
