Research scientists at VTT Technical Research Centre of Finland Ltd have
demonstrated a new technique for generating electrical energy. The new method
can be used in harvesting energy from mechanical vibrations of the environment
and converting it into electricity. Energy harvesters are needed, for example,
in wireless self-powered sensors and medical implants, where they could
ultimately replace batteries. In the future, energy harvesters can open up new
opportunities in many application areas such as wearable electronics.
Research scientists at VTT have successfully generated energy by utilizing the
charging phenomenon that occurs naturally between two bodies with different
work functions. Work function is the amount of energy needed to remove an
electron from a solid and it determines, for example, the well-known
photoelectric effect. When two conducting bodies with different work functions
are connected to each other electrically, they accumulate opposite charges.
Moving of these bodies with respect to each other generates energy because of
the attractive electrostatic force between the opposite charges. In VTT’s
experiment the energy generated by this motion was converted into useful
electrical power by connecting the bodies to an external circuit. This new
energy conversion technique also works with semiconductors.
In many sensor applications and medical implants such as pacemakers,
electricity is typically provided by batteries. Research into small energy
harvesters that turn mechanical vibration into electricity has focused on
piezoelectric and electrostatic devices. Unlike these devices VTT’s technique
does not require an integrated battery, electrets or piezo materials.
VTT estimates that the new electricity generation technology could be
introduced on an industrial scale within three to six years. Energy harvesters
and new sensing solutions are among the projected megatrends of the near
future. Energy harvesters can replace batteries and other energy sources in
applications where maintenance is difficult or impossible.
The findings of the study were published in the Scientific Reports online
The full article can be read at http://www.nature.com/srep/2014/141028/srep06799/full/srep06799.html.
Picture: Schematic of
the new electricity generation technique. Bodies 1 and 2 have different work