TUM and MIT researchers produced a glucose fuel cell that is only 400 nanometers thick. For therapeutic implants, this glucose fuel cell creates electricity utilizing the body's sugar as an energy source.
“Instead of using a battery, which accounts for 90 percent of an implant’s volume, our device can be mounted as a thin film on a silicon chip or perhaps in the future even on the surface of the implant itself,” stated Jennifer Rupp, Professor of the chemistry of solid-state electrolytes at TUM.
A cathode, anode, and electrolyte layer make up the glucose fuel cell. The anode converts glucose from the body into gluconic acid, which releases protons. The electrolyte transports these protons through the fuel cell to the cathode, where they react with air to generate water molecules. To power an electronic device, electrons pass through an external electric circuit.
“Using glucose fuel cells as a power source is not new", stated MIT’s Dr. Philipp Simons. "Previous devices used a plastic electrolyte layer. Since plastic materials are not compatible with common production processes in the semiconductor industry, it is difficult to apply them to state-of-the-art silicon chips in medical implants. Hard materials are needed for this. Another disadvantage of the plastic-based electrolytes is that the polymers made up the plastic were sometimes damaged when sterilizing the implants.”
For their innovative fuel cell, the scientists used ceramic electrolytes. The ceramic was biocompatible and small enough to fit on a silicon chip. It's also heat resistant.
150 glucose fuel cells on a chip were developed by scientists. They put the cells on silicon wafers, implying that the device may be used with a standard semiconductor material. The wafer was then immersed in a glucose solution.
Many of the cells produced a peak voltage of around 80 millivolts, which is sufficient to power sensors and a variety of other implantable electronic devices. This is the highest power density of any glucose fuel cell design to date, owing to the microscopic size of each cell.
“This is the first time that the proton conduction in electro-ceramic materials has successfully converted glucose into electricity,” Rupp added.