Over the last decade electrical batteries have emerged as a critical bottleneck for portable electronics development.
High-power mechanical energy harvesting can potentially provide a
valuable alternative to the use of batteries, but, until now, a suitable mechanical-to-electrical
energy conversion technology did not exist. Here we describe a novel mechanical-to-electrical
energy conversion method based on the reverse electrowetting phenomenon. Electrical energy
generation is achieved through the interaction of arrays of moving microscopic liquid droplets
with novel nanometer-thick multilayer dielectric fi lms. Advantages of this process include
the production of high power densities, up to 10 3 W m − 2 ; the ability to directly utilize a very
broad range of mechanical forces and displacements; and the ability to directly output a broad
range of currents and voltages, from several volts to tens of volts. These advantages make this
method uniquely suited for high-power energy harvesting from a wide variety of environmental
mechanical energy sources.