Solar power has been playing a bigger role in energy supply, and solar cell technique has been advanced. However, a fundamental limitation remains: at night, solar cells have to go to sleep, and solar power needs to be stored effectively.
Large-scale deployment of solar cells depends on scalable and inexpensive grid-level energy storage solution.
In a study conducted in University of Wisconsin-Madison, researchers integrate solar cells with a large-capacity liquid battery. This provides a more efficient, scalable, compact, and cost-effective way to store solar energy.
The finding is published in Angewandte Chemie International Edition. In the study, researchers used regenerative photo-electrochemical solar cells and electrochemical redox flow batteries (RFBs) to achieve hybrid energy conversion and storage.
Flow batteries, or redox flow batteries (after reduction-oxidation), is a type of rechargeable battery where the rechargeability is provided by two chemical components dissolved in liquids contained within the system and separated by a membrane.
A flow battery is technically akin both to a fuel cell and an electrochemical accumulator cell. It has technical advantages such as potentially separable liquid tanks and near unlimited longevity over most conventional rechargeables.
In this study, researchers mounted silicon solar cells on the reaction chamber, and energy was converted by the cell immediately charges the water-based electrolyte, which was pumped out to a storage tank.
This new device can harvest sunlight to liberate electrical charges and directly changes the oxidation-reduction state of the electrolyte on the surface of the cells. It is a single device to convert solar energy and charge a battery.
Researchers suggest that the unified design achieves a more efficient, scalable, compact, and cost-effective hybrid energy conversion and storage.
In addition, the design currently uses organic molecules rather than expensive metals. This will decrease costs in batteries. Future research will try to increase the energy storage capacity of the battery.
Citation: Wenjie Li, et al. (2016). Integrated Photoelectrochemical Solar Energy Conversion and Organic Redox Flow Battery Devices. Angewandte Chemie International Edition, published online. DOI: 10.1002/anie.201606986.
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