Researchers in the lab of Stanford Materials Scientist Yi Cui have created a water-based chemical reaction-battery that is able to store power for later use, and it may serve as a helpful grid solution in balancing out the volatility of renewable energy sources like wind and solar. With an affordable, rechargeable battery like the one this team of scientists is developing, excess solar and wind power can be saved up for when the weather isn’t providing energy or when electricity demand is high. To create this battery, the scientists created a chemical reaction that produces excess hydrogen gas, which can later be converted into electricity.
“What we’ve done is thrown a special salt into water, dropped in an electrode, and created a reversible chemical reaction that stores electrons in the form of hydrogen gas,” Cui explained.
To achieve this feat, the researchers, who were led by postdoctoral scholar Wei Chen, engineered an electron-exchange between water and manganese sulfate. Manganese sulfate is an affordable, easy-to-come-by salt used to make many products, including dry batteries. To test the battery, they attached a power source to the prototype. When the electrons from the power source reacted with the manganese sulfate in the water, particles of manganese dioxide stuck to the electrodes, while excess electrons “bubbled off” as hydrogen gas, a press release states.
The energy stored in hydrogen gas can be converted back into electricity when it is needed. The team also proved that the prototype could constitute a rechargeable battery by reattaching the power source to the depleted invention and repeating the process again and again. Their goal is to eventually create a grid-connected, utility-scale, affordable and long-lasting battery that meets Department of Energy standards.
“We believe this prototype technology will be able to meet Department of Energy goals for utility-scale electrical storage practicality,” Cui said.
The DOE has several expectations for batteries designed for grid-employment. It recommends they can store and discharge a minimum of 20 kW during an hour and be able to go through at least 5,000 recharges. The demo-battery is only 3-inches-tall and produces about 20mW hours of electricity, which Stanford News explains is comparable to a keychain LED flashlight. Cui, Chen and their colleagues feel a large, industrialized version could meet DOE standards. They also ran their prototype through 10,000 recharges – double what the DOE suggests.
The DOE is also seeking grid-scale storage solutions that have a lifespan of 10 years and cost no more than $2,00, or an average of $100 per kilowatt hour. The Stanford scientists feel the decade-long life is achievable and are currently working on the affordability of their design. It currently uses platinum as a catalyst, which is too pricey for any major grid-scale usage.
“We have identified catalysts that could bring us below the $100-per-kilowatt-hour DOE target,” Chen said. Cui is now seeking a patent on the battery and has plans to launch a company around the goal of bringing the system to market.