Stanford University-Developed Super-Fast Charging Batteries, Coming Soon To A Cellphone Near You?
Long sought as an alternative material for batteries due to its low cost, low flammability, and high-charge storage capacity, aluminum has for decades outwitted scientists looking to create an aluminum-ion battery that is able to produce sufficient voltage after repeated charge-discharge cycles. The Stanford group, though, has finally met the challenge by employing graphite as the positively charged cathode in tandem with the negatively charged aluminum anode and an ionic liquid electrolyte. The Stanford battery can withstand more than 7500 recharge cycles, whereas previous attempts at an aluminum-ion battery usually petered out after only 100 charge-discharge cycles.
Yet another significant feature of the Stanford battery is its unprecedented stability. “Lithium-ion batteries can be a fire hazard,” Dai says, "(they) can go off in an unpredictable manner - in the air, in the car, in your pocket." And for emphasis he cites recent decision by both United Airlines and Delta Airlines to ban bulk lithium-ion battery shipments on passenger jets. Regarding the Stanford battery, "...we have videos showing that you can drill through the aluminum battery pouch, and it will continue working for a while longer without catching fire."
Ming Gong, the co-lead author of the Nature study adds, "Another feature of the aluminum battery is flexibility.” He continues, “You can bend it and fold it, so it has the potential for use in flexible electronic devices. Aluminum is also a cheaper metal than Lithium."
So with the news on Stanford-model super-fast charging aluminum-ion batteries being so terrific, these world-saving bundles of energy should be super-fast-tracking into production, right? Right?
Not so fast.
Stanford's current aluminum-ion battery prototype produces about 2 volts, significantly less than the 3.6 volts derived from a conventional lithium-ion battery, and its energy density — the amount of electrical energy stored in a given unit of mass — is lower as well (40 watts per kilogram versus between 100 and 260 watts per kilogram for lithium-ion). The Stanford team is optimistic, though, that overcoming these problems is just a matter of time (and further research).
"Our battery produces about half the voltage of a typical lithium battery," Dai says. "But improving the cathode material could eventually increase the voltage and energy density. Otherwise, our battery has everything else you'd dream that a battery should have: inexpensive electrodes, good safety, high-speed charging, flexibility and long cycle life. I see this as a new battery in its early days. It's quite exciting."