This ‘two-faced’ membrane can create electricity—from nothing but salty water

Imagine being stuffed into a crowded train car and noticing a less crowded one just down the platform. You’d probably want to move over as soon as possible. Particles that follow this balancing act—known as osmosis—spontaneously move from an area of high concentration to one of low concentration. Now, scientists have used this tendency to create a power-producing membrane that can harvest electric current from nothing but salty water