Researchers at Ohio State University have developed a thin, plastic membrane that keeps rechargeable batteries from discharging while not in use and allows for faster recharging.
The new technology, called an ionic redox transistor, controls how charge flows inside a battery, inspired in part by how living cell membranes transport proteins in the body.
The transistor could be used for high-powered supercapacitors in electric cars and could even help prevent the fires plaguing some hoverboard models.
Vishnu-Baba Sundaresan, leader of the study and assistant professor of mechanical and aerospace engineering at OSU, and doctoral student Travis Hery are using the ionic redox transistor to develop a new kind of battery in which energy is stored in a liquid electrolyte, which people can recharge or empty out and refill as they would a gas tank.
“For everyday commuting, the electrolyte can be simply regenerated by plugging it into a power outlet overnight or while parked at the garage,” Sundaresan said. “For long road trips, you could empty out the used electrolyte and refill the battery to get the kind of long driving range we are accustomed to with internal combustion engines.”
During the research process, the OSU researchers discovered the best eco-car makers have hit a performance limit at 0.4 miles of driving per minute of charging, or about 200 miles after an eight-hour charge. Gas-powered cars can cover the same distance after only one minute at the pump. The membrane may boost electric car batteries to provide double-digit miles per minute of charge.
“That’s still an order of magnitude away from the equivalent measure in gasoline, but it’s a place to start,” said Sundaresan.
Hybrid and electric cars are hitting this performance limit, Sundaresan said, because of how charge is stored in conventional batteries, and the membrane technology could be the only way to push past this limit until a new category of battery electrodes is developed.
“Research over the last 50-plus years has focused on advancing the chemistry of battery electrodes to increase capacity,” he said. “We’ve done that, but the increase in capacity has come at a cost of robustness and the ability to rapidly charge and discharge batteries. Electric vehicle design is mature enough now that we know the limit they’re reaching is because of the chemistry of lithium-ion batteries.”
Batteries like lithium-ion batteries already have membrane separators that conduct charge and physically separate the anode and the cathode from each other, but those lose charge over time because the membranes can’t completely prevent charge from leaking between the anode and cathode. This causes the battery’s internal energy to convert to heat, which is a gradual power drain at best, and in some cases, overheating can lead to battery fires.
The university is in the process of licensing the technology for further development.
Filed Under: Capacitors, Rapid prototyping