A US-led research collaboration including a team of PV scientists from Australia has produced an ultra-efficient and long-lasting solar flow battery – a way to generate, store and re-deliver renewable electricity from the sun in one device, Renew Economy reports.
Chemists from the Song Jin lab at the University of Wisconsin-Madison said on Tuesday that the new device was made of silicon solar cells combined with advanced solar materials and integrated with optimally designed chemical storage components.
Essentially, they combine the advantages of photovoltaic cells that convert sunlight into electricity with the advantages of flow batteries, which use tanks of chemicals that can react to produce electricity and be recharged by the solar cells.
The research team says that the solar flow battery produced through the collaboration has set a new record efficiency of 20 per cent, besting most commercially available silicon solar cells, and was 40 per cent more efficient than the previous record holder for solar flow batteries, also developed by the Jin lab.
The work was done in collaboration with researchers from the University of New South Wales and the University of Sydney in Australia, Utah State University, King Abdullah University of Science and Technology in Saudi Arabia and the City University of Hong Kong. It was published on July 13 in the journal Nature Materials.
Lead author of the study, UW–Madison graduate student Wenjie Li, said that while solar flow batteries were years away from commercialisation, they offered the potential to provide reliable electricity generation and storage for lighting, cell phones or other fundamental uses for homes in remote areas.
On the solar side, the team tapped halide perovskites, the solar conversion efficiency of which has dramatically increased from a few per cent to over 25 per cent in 10 years. To this, they added silicon, which remains key for making a stable device that can withstand the chemicals in a flow battery.
And this is where the Australian team came into play. Professor Anita Ho-Baillie (Uni Syd) and postdoctoral researcher Jianghui Zheng (UNSW) fabricated the perovskite-silicon solar cells with an additional protection layer on the silicon surface and shipped them to Wisconsin for testing.
“Our motivation for the design of the solar cell was to combine these two materials together so we have both high efficiency and good stability,” said Li.
For the flow battery, Li used theoretical modelling to select a pair of chemicals to operate at the ideal voltage based on the characteristics of the solar cell, maximising efficiency. The chemicals are readily available, cheap organic compounds which are dissolved in a benign water solution of table salt rather than strong acids.
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