An international team of scientists lead by Honjie Dai at Stanford University have stumbled upon a significant find; a battery made from aluminum, that charges in one minute.
Not only can the battery be rapidly charged, but it lasts upwards of 7,500 charge-discharge cycles without capacity decay, as opposed to a lithium battery’s 1,000 cycles, and the battery can be bent or even drilled through without losing functionality.
Every battery has a negatively charged anode and a positively charged cathode. Although aluminum anodes work fine, they hadn’t been able to find a substance that could function as a cathode while maintaining voltage discharge after discharge, until now.
Dai and his team realized that graphite is the perfect cathode; it’s durable, cheap and can hold the charge needed to keep the energy flowing for a long time.
“People have tried different kinds of materials for the cathode,” Dai said. “We accidentally discovered that a simple solution is to use graphite, which is basically carbon. In our study, we identified a few types of graphite material that give us very good performance.”
The earliest prototypes only produce around 2 Volts, less than the 3.6 Volts of a lithium-ion. An added advantage compared to lithium-ion batteries, however, is that “lithium-ion batteries can be a fire hazard.” says Dai.
“In our study, 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,” Dai said. “But lithium batteries can go off in an unpredictable manner – in the air, the car or in your pocket. Besides safety, we have achieved major breakthroughs in aluminum battery performance.”
The paper published in Nature states: “The present Al/graphite battery can afford an energy density of ~40Wh/kg (comparable to lead-acid and Ni–MH batteries, with room for improvement by optimizing the graphitic electrodes and by developing other novel cathode materials) and a high power density, up to 3,000W/kg (similar to supercapacitors).”
