Australian researchers have set a new world efficiency record for the direct synthesis of sustainable hydrogen from solar energy using low-cost materials by combining advancements in next-generation solar cells with electrolysis developed in Australia.
The researchers from the Australian National University and the University of New South Wales reached the milestone, which is being hailed as a significant step in lowering the cost of renewable hydrogen production.
The study describes how the researchers leveraged cutting-edge developments in next-generation ‘tandem’ solar cells in conjunction with advancements in electrolysis procedures to reach a sun-to-hydrogen conversion efficiency of better than 20%.
The researchers used low-cost silicon-perovskite ‘tandem’ solar cells optimized for hydrogen production, which combined two different types of solar cells layered on top of one another to achieve a combined efficiency of 24.3% – significantly higher than the efficiency of most conventional silicon solar cells.
The scientists then paired the high-efficiency tandem solar cells with inexpensive catalyst materials to electrolyze water and separate it into hydrogen and oxygen. The researchers were able to reach a conversion efficiency of more than 20% by using low-cost components to fabricate the direct solar-to-hydrogen system.
The researchers stated that they met a conversion efficiency benchmark established by the US Department of Energy as part of its efforts to minimize the cost of renewable hydrogen production.
Additionally, the team is sure that additional research will eventually enable them to beat the Morrison government’s aim of creating hydrogen for less than $2 per kilogram.
While the current cost of hydrogen production makes it uncompetitive for a variety of applications – particularly those involving the energy system – rapidly falling costs could result in hydrogen becoming an affordable alternative to a variety of fossil fuel-derived sources, including transportation fuels and energy used as a source of industrial heat.