Electric eels inspire ‘jelly battery’

Electric eels stun their prey with modified muscle cells called electrocytes. Like electrocytes, the jelly-like materials developed by Cambridge University researchers have a layered structure that makes them capable of delivering an electric current.  

The so-called jelly batteries can stretch to over ten times their original length without affecting their conductivity – the first time that such stretchability and conductivity has been combined in a single material, the team reported. Their results are detailed in Science Advances.

The ‘jelly batteries’ are made from hydrogels, which are polymer networks that contain water. The polymers are held together by reversible on/off interactions that control the jelly’s mechanical properties.

The ability to precisely control mechanical properties and mimic the characteristics of human tissue makes hydrogels suitable for soft robotics and bioelectronics; but they need to be conductive and stretchy for such applications.

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In a statement, first author Stephen O’Neill, from Cambridge’s Yusuf Hamied Department of Chemistry, said: “It’s difficult to design a material that is both highly stretchable and highly conductive, since those two properties are normally at odds with one another. Typically, conductivity decreases when a material is stretched.”