Frustrated by how quickly your battery runs out? Imagine not having to worry about that anymore.
The team of researchers was led by the National University of Singapore (NUS) has made a major breakthrough in energy "harvesting" technology that could eliminate the need for batteries in various electronic devices. They have successfully developed a new rectifier that can convert normally wasted radio frequency (RF) signals, such as Wi-Fi and cellular network signals, into usable direct current (DC) energy.
With this technology, a future where you never have to worry about your gadgets running out of battery power could become a reality. This revolutionary research was published in Nature Electronics on July 24, 2024.
What is Energy "Harvesting"?
“Harvesting” is the process of collecting and converting ambient energy into usable power. This technology enables small devices to utilize RF signals to reduce reliance on batteries, extend their lifespan, and reduce environmental impact.
It also allows devices in remote locations to be powered remotely without the need to physically replace batteries. With this technology, the use of wireless sensor networks and IoT devices in hard-to-reach areas becomes more practical and sustainable.
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Overcoming the Limitations
Unfortunately, this technology still has some limitations. The captured radio signals must be close to the electronic devices. In addition, existing tools, such as Schottky diodes, are inefficient at converting weak radio signals (typically below -20 dBm) into electricity.
However, NUS scientists have managed to solve this problem by developing a new tool that is much more sensitive and efficient. Using a nanoscale spin rectifier (SR), this technology can convert low-power RF signals with higher efficiency.
At the core of the technology is an extremely small magnetic tunnel junction (MTJ) made of a special CoFeB/MgO material that is commonly used in computer memory. The researchers modified this MTJ to convert radio signals into electricity. They succeeded in creating a highly sensitive device that can convert even weak radio signals into enough energy to power a temperature sensor.
By integrating the nanoscale spin rectifier (SR) into an energy harvesting module, the research team was able to power a commercial temperature sensor at -27 dBm. The harvested energy was sufficient to power an LED and a commercial temperature sensor, with an array of 10 optimized rectifiers achieving 7.8% efficiency and high sensitivity.
A Battery-Free Future: What's Next?
The researchers are now working on integrating on-chip antennas to improve the efficiency and compactness of their technology. They are also exploring the use of series-parallel interconnects and on-chip communications to optimize RF power harvesting and generate sufficient voltage without the need for a DC booster.
These advances have the potential to eliminate the need for batteries in many electronic devices, creating more self-sufficient and environmentally friendly devices that can operate for longer periods without recharging, especially in remote or hard-to-reach locations.
