Electrochemical Process Generates Energy from Motion

This diagram illustrates the principle behind the proposed energy-harvesting system. Two metal electrodes made of lithium-alloye silicon form a sandwich around a polymer electrolyte. Bending the battery forces the ions to move across the electrolyte completing the AC circuit. (Image courtesy of MIT.)
MIT researchers have developed a new electrochemical method that harvests energy from everyday motions, like walking or running.

A small but near continuous amount of electricity is generated by motion to be used in biomedical, mechanical or environmental industries. The technology used for the device is comparable to that of lithium ion batteries, ultimately reducing production costs on a large scale.

This electrochemical process consists of two sheets of lithium alloys that act as electrodes. These electrodes are separated by an absorbent polymer that is saturated with a liquid electrolyte.

As mechanical energy is transferred to the battery it will start to bend. This bending will create a pressure build-up that pushes the lithium ions throughout the polymer. A counteracting voltage and electrical current is created, which runs through the external circuit, dividing the two electrodes. This AC current allows the battery to power other devices like wearables and sensors.

The device doesn’t need to be bent significantly to produce a voltage. A small weight attached to one end of the device allows the metal to slightly bend when the user is moving their arm or leg.

MIT engineers claim the system is stable because there is little evidence of decline in performance after as many as 1,500 cycles.

Integration with wearable technology is an ideal application for the battery as its flexibility combined with natural human motion will result in power generation.

MIT researchers suggest the method could also be used as an actuator in biomedical systems and as a mechanism to detect stress in roads, bridges or other settings and structures.

This technique could be utilized in other electrochemistry applications like:

·         Flexible Electronics,

·         Self-Powered Sensors,

·         Wearable Devices,

·         Human-Machine Interfaces,

·         Robotics and

·         Artificial Skin.

For more information about this process, visit MIT’s webpage.