24 November, 2020
The power we generate from hydro dams, wind turbines and solar panels – and put into our electric cars – could be supercharged by using electronics made out of a revolutionary new material, a Kiwi researcher says.
MacDiarmid Institute and University of Canterbury researcher Martin Allen is investigating the material gallium oxide as a replacement for the silicon we currently use in electronic devices. The new electronics are “faster, smaller and more efficient”, he said.
As the world will increasingly replace fossil fuels with renewable energy, a material that converts and conducts electricity more efficiently could give us more bang for our buck out of current – and future – renewable power stations.
When electricity runs through silicon circuitry, some power is lost as heat. That is why your laptop heats up when running and comes with a fan to cool it down if temperatures get too high.
In contrast, electronics made from gallium oxide are more efficient – the heat losses are not as high and more power remains for the task at hand.
“That immediately saves emissions. And New Zealand is a particularly important place to do this in because we have already got 85 per cent renewable energy,” Allen said.
Silicon stops working when it gets much above 100 degrees Celsius. Although gallium oxide creates less heat, the electronics still work even when the mercury is as high as 500C, Allen’s team discovered.
“We were blown away,” Allen said. “In fact, instead of getting damaged, they seem to be getting better and better under high temperatures.”
he researchers published this finding in the journal of Applied Physics Letters.
“This is a bonus discovery. You do not need to aggressively cool them, which means you do not need bulky cooling systems,” he added.
The team will continue to test gallium oxide’s ability to handle the heat. The material is being studied by other researchers overseas, though the MacDiarmid Institute is interested in its use in particular electronics: Schottky diodes and transistors. These devices “switch and control electricity”, Allen said.
For example, solar panels on the roofs of offices or homes generate low-voltage DC (direct current) electricity, he said.
“To use that, you have got to convert it to AC (alternating current). Every time you want to convert it, to use it, you have got to use diodes and transistors. Every time you do that, you pay a price in terms of lost energy,” he added. “So if we can improve that efficiency, then immediately you are not wasting your valuable renewable resource.”
Heat is also an issue for electric cars, particularly during fast-charging, Allen said. “It is really energy intensive and then your system does need to be cooled with fans and things like that, otherwise it will heat up and burn out.”
Gallium oxide electronics would fill the battery faster, produce less heat and suffer less damage should circuit temperatures rise, he said. “You use less space and less weight, which is really important for electric vehicles.”
Allen estimates high-voltage electronics made using the material could start to replace silicon versions in five years’ time.
“The main thing we have to do now is prototype these devices,” he said. “You really do have to demonstrate the reliability of anything you bring to the market. Theoretically, this stuff knocks it out of the park.”
Allen said his team’s electronics would be used initially in devices and systems that must survive very high temperatures, such as fire and geothermal power station sensors.
Gallium oxide could be produced in a similar way to silicon, he said. “That should keep the costs under control.”