Researchers at The Australian National University (ANU) have achieved a new efficiency record for hydrogen cells that can convert water into hydrogen simply using sunlight.
Lead author, Dr Siva Karuturi (pictured) says hydrogen has an important role to play in solving the intermittency of renewable energy sources.
“There are significant cost benefits to this solar-to-hydrogen approach as it eliminates the need for added infrastructure that’s necessary when hydrogen is produced using an electrolyser.”
He said previous methods of converting water to hydrogen had produced a low overall energy conversion efficiency but his research had improved this.
“To produce hydrogen in the past, solar plants had to produce electricity which is then used to electrolyse water to produce hydrogen. This new method is more direct, making it more efficient,” Dr Karuturi said.
The unique approach outlined in the ANU study also used inexpensive semiconductor materials and resulted in a 17.6 per cent solar-to-hydrogen efficiency.
This is nearing the efficiency of solar panels being installed on rooftops, which have an efficiency of around 20 per cent, Dr Karuturi said.
He said the ANU was working towards reaching an efficiency of 20 per cent in the coming months, which would pave the way for low-cost green hydrogen production.
The research team used a “tandem” light absorber structure- placing a perovskite cell on top of a specially-made Si electrode.
Co-author, Dr Heping Shen says with extraordinary optoelectronic properties, the perovskite materials offer great potential for low-cost, high-efficiency tandem devices with Si.
“Together with unprecedented progress in efficiency, the perovskite material has also undergone significant improvement for its stability, making it one of the most attractive candidates for the solar industry,” Dr Shen said.
This new method makes use of noble-metal catalysts such as platinum and Dr Karuturi says that they are working to replace them with cheap materials to further reduce costs in the future.
He said another major outcome for the research would be Australia’s ability to more efficiently export hydrogen.
Dr Karuturi noted that last year the Council of Australian Governments (COAG) Energy Council approved a national hydrogen strategy which aims to enable a hydrogen economy.
“This strategy is important to Australia and our hope is that this new, direct method of converting water to hydrogen can aid these efforts,” said Dr Karuturi.
The research has been published in Advanced Energy Materials.
