A New Kind of Soft Battery, Inspired by the Electric Eel.
Researchers took a cue from the electric eel to create a soft, foldable battery that could one day power devices like pacemakers.
Electric eels, which slither along the muddy bottoms of ponds and streams in the Amazon and Orinoco river basins of South America, can cause a shock powerful enough to knock a horse off its feet. Their power comes from cells called electrocytes that discharge when the eel is hunting or feels threatened.Electric eels can synchronize the charging and discharging of thousands of cells in their bodies simultaneously, says Max Shtein, a materials scientist at the University of Michigan who worked on the research.
The electrocytes of an electric eel are large and flat, with hundreds stacked together horizontally. Because of the way they’re stacked, the cells’ tiny individual voltages add up to a significant kick. This is possible because the surrounding tissue insulates the electrocytes so the voltage flows forward to the water in front of the fish – stunning or killing prey or threats – then flows back to create a complete circuit.
A team led by Shtein’s collaborator Michael Meyer at the University of Fribourg tried to copy the eel’s physiology by creating about 2,500 units made of sodium and chloride dissolved in water-based hydrogels. They printed out rows of tiny multicolored buttons of hydrogels on long sheets of plastic, alternating the salty hydrogels with ones made just with water. They then printed out a second sheet of charge-selective hydrogels, each one allowing either positively charged sodium or negatively charged chloride gels to pass through. When the sheets were folded, using a special origami technique, the alternating gels touched and generated electricity. The system generated 110 volts – a decent jolt, but far less than the power output of an eel, which has thinner, lower-resistance cells.The team, which also included researchers from the University of Fribourg and the University of California, San Diego, wrote about their prototype in the journal Nature last month.
The hydrogel system is soft and flexible, which could make it a potentially good power source for soft-bodied robots whose movements would be impeded by hard batteries. It’s also free from the potentially toxic ingredients of traditional batteries, such as lead. And since the system is made from artificial components rather than biological tissue, it has a low potential for immune rejection.
Recent status of this research.
We need a lot of these little cells to generate much electricity to fulfil our needs. Right now the researchers have only generated 110 volts from these soft batteries, but they’re working on more.Soon we will have soft batteries and soft robots in our future that will help us to work in various environments in a very human friendly nature and fulfil our needs in more efficient way.