Chemists at the University of Wisconsin-Madison and their collaborators have created a highly efficient and long-lasting solar flow battery, a way to generate, store and redeliver renewable electricity from the sun in one device.
The new device is made of silicon solar cells combined with advanced solar materials integrated with optimally designed chemical components. The solar flow battery achieved a new record efficiency of 20 percent. That bests most commercially available silicon solar cells used today and is 40 percent more efficient than the previous record holder for solar flow batteries.
While solar flow batteries are years away from commercialization, they offer the potential to provide reliable electricity generation and storage for lighting, cell phones or other fundamental uses for homes in remote areas. 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 researchers published their work in the journal Nature Materials.
Since the sun doesn’t always shine, storage is key for practical solar electricity, especially in remote and rural regions with a lot of sunlight, such as in the sunbelt regions of the U.S., Australia, Saudi Arabia and Africa. Many solar home systems use lead-acid or lithium-ion batteries for electricity storage. Flow batteries, which use large tanks of liquid chemicals to store energy, could be less expensive at a larger scale and are an ideal storage choice for merging with solar cells.
The research team has spent years studying and improving integrated solar flow battery systems. In 2018, it developed a solar flow battery using a triple layer of efficient but expensive solar materials that achieved an overall efficiency of 14 percent. However, corrosion greatly reduced the device’s lifetime.
In their latest report, the researchers turned to an increasingly popular material for photovoltaic cells, halide perovskites. The solar conversion efficiency of these special materials has dramatically increased from a few percent to over 25 percent in 10 years. Recent research has shown that halide perovskites can also increase the efficiency of traditional silicon solar cells by capturing more energy from the sun.
This new breed of highly efficient perovskite-silicon solar cells is on its way to commercialization. Yet silicon remains key for making a stable device that can withstand the chemicals in a flow battery.
The research team wanted to combine these two materials together so thet have both high efficiency and good stability.
News Source: Eurekalert
