An international group of scientists claims to have created a high-efficiency, low-cost redox flow battery powered by perovskite-silicon tandem solar cells which combines storage and power production in one unit.
The device was developed by researchers from the Wisconsin-Madison and Utah State universities in the United States, the universities of New South Wales and Sydney in Australia, the King Abdullah University of Science and Technology in Saudi Arabia and the City University of Hong Kong.
The researchers describe their device as ideal for lighting or recharging mobile phones in off-grid areas.
The scientists said the integrated solar flow storage system combines photo-electrochemical solar cells with aqueous organic redox-flow battery technology and has solar-to-output efficiency of 20.1%. The battery is an evolution of an abandoned solar flow battery researcher Song Jin and his colleagues developed in 2018. That project fell by the wayside due to the costs of the solar materials used at the time, poor solar-to-output efficiency of 14% and a short device lifetime.
The new device, offering a longer lifespan, better solar power conversion utilization ratio and capacity utilization rate, has an optimal voltage match, according to its developers. They used theoretical modeling to identify chemicals in the flow battery which would operate at the ideal voltage, based on the characteristics of the perovskite solar cells, which were manufactured with an additional protective layer on the silicon surface. “The chemicals are organic compounds, not expensive metals as in traditional flow batteries, and are dissolved in a benign water solution of table salt rather than strong acids,” the group said.
The developers said further research is needed to make the solar flow battery a practical solution for the off-grid market. “Increasing the size and scale of the current small gadgets in the research lab is one challenge,” they said.
The device is described in the study High-performance solar flow battery powered by a perovskite/silicon tandem solar cell, published in Nature Materials.