Cheap battery stores energy for a rainy day
Over the past few decades, researchers have investigated many other chemical systems, and ruled all but a handful out. “The periodic table has been pretty well picked over,” says Aziz. “So we’ve introduced the world of organic chemistry to this problem.”
His battery’s anode uses a solution of sulphuric acid containing a type of organic compound known as a quinone. The quinone is cheap and needs no catalytic urging to react with protons to form a higher-energy hydroquinone, thereby charging the battery. Aziz teamed this half of the flow battery with a well-known partner: a cathode that alternates between bromine and hydrobromic acid.
The quinone–hydroquinone reaction is about 1,000 times faster than the rival vanadium reaction, allowing the battery to charge and discharge rapidly. And by changing some of the quinone’s chemical groups, Aziz can alter their solubility and even the voltage of the flow battery, fine-tuning the system. The battery, unveiled today in Nature1, has completed 100 charge–discharge cycles with no sign of degradation (although a commercial system would probably need to top 10,000 cycles).