New Material Moves Seawater Batteries Step Closer to Primetime

­As the world makes more use of renewable energy sources, new battery technology is needed to store electricity for the times when the sun isn’t shining, and the wind isn’t blowing.

“Current lithium batteries have reached their limitations in terms of energy storage capability, life cycle, and safety,” says Xiaolei Wang, a professor of chemical engineering at the University of Alberta in Edmonton. “They’re good for applications like electric vehicles and portable electronics, but they’re not suitable for large-scale grid-level energy storage.”

With the help of the Canadian Light Source at the University of Saskatchewan, Wang and his team are developing new technologies to help make grid-level aqueous batteries that can use seawater as an electrolyte. Aqueous batteries can be safer, cheaper, and more environmentally friendly to make and dispose of than lithium-ion batteries, but their development has so far been limited by a lack of a good material to make a decent anode (the part of the battery where electricity flows out). 

Wang’s team developed a material made of polymer nanosheets and carbon nanotubes that is suitable for storing a variety of different types of ions, including those found naturally in seawater. These anodes are thicker than previous ones, so have a high capacity for storing energy, and are extremely durable so they can last a long time – up to 380,000 charging cycles in some cases – and they can operate under extreme conditions such as fast charging and discharging, or at low temperatures, says Wang.

The ultrabright synchrotron light at the CLS was vital in understanding the microstructure of the anode material and its electrochemical behaviour. “The success of our project could not have been realised without CLS,” says Wang.

Aqueous batteries based on this new anode technology could, he says, help realize universal energy storage, greatly expanding the options for renewable energy. “In Canada we have a lot of renewable energy resources. If we can use this type of battery technology to store that energy, we can have reliable, safer, and affordable batteries for everyone.”