Pint and his team used scraps of steel and brass – two of the most commonly discarded materials – to create a battery that can store energy at levels comparable to those of lead-acid batteries while charging and discharging at rates comparable to supercapacitors.
According to the team, the performance is enabled by anodisation. When the metals were anodised using a common household chemical and residential electrical current, the researchers found the metal surfaces were restructured into nanometre-sized networks of metal oxide that can store and release energy when they react with potassium hydroxide, a water based liquid electrolyte.
These nanometre domains are said to explain the fast charging behaviour, as well as the battery’s stability: the battery was tested for 5000 consecutive charging cycles – the equivalent of more than 13 years of daily charging and discharging – after which, it retained more than 90% of its capacity.
The team's next step is to build a full-scale prototype battery suitable for use in energy-efficient smart homes.
“We’re forging new ground with this project,” Pint concluded. “It’s a completely new way of thinking about battery research and it could bypass the barriers holding back innovation in grid scale energy storage.”