Scientists develop recyclable ‘water batteries’ that never explode

Researchers in Australia are claiming to have devised an innovative ‘water battery’ that doesn’t rely on a flammable electrolyte. This path-breaking technology will not only serve as an alternative for storing renewable energy but will also seek to replace traditional lithium-ion varieties that are considered less safe.

“What we design and manufacture are called aqueous metal-ion batteries – or we can call them water batteries,” said lead author Professor Tianyi Ma of RMIT University.

Why water batteries are safer?

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Batteries are made up of three main parts: a positive electrode called the cathode, a negative electrode called the anode, and an electrolyte that moves ions between these electrodes.

The researchers from RMIT have developed what they call "water batteries" by replacing traditional electrolytes with water mixed with simple salts. They claim that these water-based batteries are safer and less harmful. These batteries use metals like magnesium or zinc, which are cheaper and better for the environment compared to lithium or lead-acid batteries.

Using water as an electrolyte in batteries could help prevent a common problem called dendrite growth. Dendrites are tiny metal spikes that can cause batteries to short-circuit. To solve this issue, scientists coated the battery's anode with bismuth metal, which forms a protective rust-like layer when oxidised.

This coating helps the battery last longer, with prototypes retaining over 85 per cent of their capacity even after being charged and discharged 500 times, which is when most lithium-ion batteries start to fail.

“Our batteries now last significantly longer – comparable to the commercial lithium-ion batteries in the market – making them ideal for high-speed and intensive use in real-world applications,” Ma said.

“With impressive capacity and extended lifespan, we’ve not only advanced battery technology but also successfully integrated our design with solar panels, showcasing efficient and stable renewable energy storage,” he added.

Several prototypes developed

Researchers have developed several prototypes of water batteries, ranging from coin-sized batteries suitable for clocks to larger cylindrical batteries akin to the common AA or AAA you buy from any gas station.

“The next step is to increase the energy density of our water batteries by developing new nanomaterials as the electrode materials,” Ma said.

(With inputs from agencies)