Researchers suggest a stable way to store the renewable energy for electric vehicle charging infrastructures.
Electric vehicles are gaining traction and their sales have grown exponentially in the past few years. Thus, increased the demand for renewable energy sources to power them, such as solar and wind. EVs require power to be available anywhere and anytime, without delays in recharging, but solar and wind are intermittent energy sources that are not available on demand. The energy generated needs to be stored for later use.
Dr. Yu Zhu, a professor in University of Akron’s School of Polymer Science and Polymer Engineering, suggests a stable way to store this important energy. According to the researchers, low-cost, scalable redox flow batteries (RFB) are among the most suitable technology for such a system.
However, RFBs use environmentally hazardous active materials (electrolytes). Recently, water-soluble organic materials have been proposed as future electrolytes in the RFBs, namely aqueous organic RFBs, or AORFBs. The organic electrolytes are renewable and can be manufactured easily with low-cost. However, stability is the main issue.\
The researchers developed a stable catholyte (positive electrolyte), and demonstrated cells that kept more than 90 percent of capacity over 6,000 cycles, projecting more than 16 years of uninterrupted service at a pace of one cycle per day.
“Development of high-performance RFBs will enrich the category of electricity energy storage systems and complement the shortcoming of intermittent renewable energy sources, therefore largely improving the usability of electricity powered facilities, such as vehicles,” says Zhu. “To significantly improve the performance of aqueous organic RFBs, the urgency of developing new catholyte is crucial.”
Their work has been published in the journal Nature Energy. In their paper, researchers report how they enhanced the solubility of catholyte in water. Instead of attaching a hydrophilic functional group to improve the solubility of the molecules, the researchers change the symmetry of molecules, which results in a dramatic enhancement of solubility. With this new development, researchers plan to design new materials that can further mature the RFBs.