New 'smart' membrane may give electric car more mileage

In a bid to improve on the miles that most electric cars get per minute of charge, researchers, led by an Indian-origin engineer, have designed a thin plastic membrane that stops rechargeable batteries from discharging when not in use and allows for rapid recharging.
The patent-pending technology controls how charge flows inside a battery, and was inspired by how living cell membranes transport proteins in the body.
It could be applied in high powered 'supercapacitors' for electric cars and even help prevent the kinds of fires that plague some models of hoverboards, researchers said.
Researchers at the Ohio State University in the US hope the "smart" membrane will enable the development of a new category of fast-charging and powerful batteries called "redox transistor batteries" for automobiles that will travel farther on a single charge.

The best eco-car makers appear to have hit a performance limit, and that limit is 0.4 miles - less than half a mile of driving - per minute of charging, researchers said.
Today's very best eco-friendly cars can travel around 200 miles after an 8-hour charge, while gas-powered cars can cover the same distance after only one minute spent at the pump.

Researchers hope their technology can boost electric car batteries to provide up to tens of miles per minute of charge.
"That is still an order of magnitude away from the equivalent measure in gasoline, but it's a place to start," said Vishnu-Baba Sundaresan, an assistant professor at Ohio State and leader of the study.

Sundaresan said that today's hybrid and electric cars are hitting the performance limit because of how charge is stored in conventional batteries.
He also believes that his new membrane technology might be the only way to push past that limit until entirely a new category of battery electrodes are developed.
Sundaresan and doctoral student Travis Hery are using their invention to develop a new kind of battery in which energy is stored in a liquid electrolyte - which people can recharge or empty and refill as they would refill 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.

"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," Sundaresan said.
Lithium-ion batteries already have membrane separators that conduct charge and physically separate the anode and the cathode from each other, but even the best of these batteries lose charge over time.
Sundaresan and Hery believe their membrane, when used with a specially designed electronic control unit, can shut down charge transport and prevent thermal runaway at its onset.
The research was published in the journal Energy & Environmental Science.