Researchers at the Stanford University have developed a water-based battery that could provide a cheap way to store wind or solar energy generated when the sun is shining and the wind is blowing so it can be fed back into the electric grid and be redistributed when the demand is high.
The battery uses a cheap industrial salt— manganese sulphate—to go through the chemical process which stores the excess energy in form of hydrogen gas.
“What we’ve done is thrown a special salt into water, dropped in an electrode, and created a reversible chemical reaction that stores electrons in the form of hydrogen gas,” Yi Cui, professor of materials science at Stanford and senior author on the research paper, explained the project.
He added that manganese-hydrogen battery technology could be one of the missing pieces in the energy puzzle – a way to store unpredictable wind or solar energy so as to lessen the need to burn reliable but carbon-emitting fossil fuels when the renewable sources aren’t available.
The team which developed the prototype of the device attached a power source to the battery to mimic power fed by solar or wind energy. The electrons flowing in reacted with the manganese sulphate dissolved in the water to leave particles of manganese dioxide clinging to the electrodes. Excess electrons bubbled off as hydrogen gas, thus storing that energy for future use.
Engineers already know how to re-create electricity from the energy stored in hydrogen gas, thus the team focussed on making the battery rechargeable.
The researchers re-attached device’s power source to the depleted prototype, this time with the goal of inducing the manganese dioxide particles clinging to the electrode to combine with water, replenishing the manganese sulfate salt. Once this salt was restored, incoming electrons became surplus, and excess power could bubble off as hydrogen gas, in a process that can be repeated again and again.
Though, currently, the prototype is just three inches tall and generates a mere 20 milliwatt-hours of electricity, around the same as LED flashlights that hang on a key ring, the researchers said that it can be easily scaled to an industrial-grade system that could charge and recharge up to 10,000 times, creating a grid-scale battery with a useful lifespan in excess of a decade.
Cui estimated that, given the water-based battery’s expected lifespan, it would cost a penny to store enough electricity to power a 100-watt lightbulb for twelve hours.
Despite a shift in focus towards renewable resources in recent decades, International Energy Agency data shows that fossil fuels continue to constitute above 80 percent of world’s total energy needs. They also are major contributors towards the global CO2 emissions.
The device is specifically developed to tap the variability of renewable energy sources—sunlight and wind—and, can also form as a backup against demand surge our outages.
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