Soft-robotics involves making technology that is similar to biological material, like we often find in nature and within ourselves. However, there’s something still holding soft robots back from taking over the squishy parts of the world, and that is batteries.
Usually, electricity and water don’t mix. Unless you’re one, very specialized animal: the electrophorus electricus, commonly known as the electric eel. If we can copy the technology that evolution gave the electric eel, then we can unlock these organic looking creations from dry land with “soft batteries!”
These strange long fish can generate electricity with an organ containing cells called electrocytes. Electrocytes by themselves can’t do much damage, but jammed up all together, they can give a shock of up to 600 volts. By analyzing the eels, scientists realized the electrocytes are organized in long stacked compartments with extra fluid space in between.
They looked at each component in the eel’s electrocyte and mimicked the same idea into alternating patterns of saltwater and freshwater hydrogels. Saltwater has salt in it, meaning it’s an electrolyte. Here, the red gels are filled with saltwater, and the blues are filled with freshwater. At the points where they touch, the negative ions from within the saltwater flow towards the empty freshwater.