When pyroelectric materials are heated, their polarization changes, leading to an electron flow that generates energy. These materials are commonly used in household devices like motion sensor lights, which detect body heat to determine when someone is near.
Anytime there is a catalytic reaction, heat is generated. These devices harness that heat and use it as energy; for example, a combustion engine in a car produces heat that, with this kind of technology, could be used to power the electrical functions of the car that otherwise rely on battery power.
The technology developed in this work is portable and has an extended lifetime. It uses on-chip combustion of methanol, a high-energy fuel, to harness energy from the reaction. The pyroelec-formed in a solid electrolyte (SE), resolv-teries tend to form dendrites — tree-like ing an issue that can hamper the perfor-metallic microstructures that can appear tric material converts waste heat from the reaction to usable power.
Vapor of a high-energy fuel — in this case, methanol — is combusted on a thin, 440-nanometer film on platinized silicon wafers. The device converts the heat from this reaction into pyroelectric power.
Nanostructured iridium oxide is the top electrode and combustion catalyst. Iridium is a dense, corrosion- and heat-resistant metal, making it an excellent candidate for this application.
Iridium oxide is first activated at temperatures as low as 105 °C and fully catalyzes methanol to carbon dioxide at 120 °C. This is an advantage compared to platinum-based catalysts, which do not achieve full conversion until 150 °C. This means less heat must be applied to the device for it to be fully effective. The on-chip combustion technology has a 90 percent combustion efficiency rate.
This technology would be significantly more powerful than lithium-ion batteries, the common rechargeable batteries used in electronics. The energy density of methanol is 22 times greater than a lithium-ion battery.
Pyroelectric power is a clean alternative to fossil fuels and nuclear energy, which still constitute more than 80 percent of the United States’ power. Thus, this technology has broad energy applications on large and small scales.