  We demonstrate a new paradigm for the wireless harvesting of mechanical
energy via a 3D-printed triboelectric nanogenerator (TENG) which comprises a
graphene polylactic acid (gPLA) nanocomposite and Teflon. The synergistic
combination of eco-friendly PLA with graphene in our TENG exhibited an output
voltage > 2 kV with an instantaneous peak power of 70 mW, which in turn
generated a strong electric field to enable the wireless transmission of
harvested energy over a distance of 3 m. Specifically, we demonstrate wireless
and secure actuatation of smart-home applications such as smart tint windows,
temperature sensors, liquid crystal displays, and security alarms either with a
single or a specific user-defined passcode of mechanical pulses (e.g.,
Fibonacci sequence). Notably, such high electric output of a gPLA-based TENG
enabled unprecedented wireless transmission of harvested mechanical energy into
a capacitor, thus obviating the need for additional electronics or energy
sources. The scalable additive manufacturing approach for gPLA-based TENGs,
along with their high electrical output can revolutionize the present method of
harnessing the mechanical energy available in our environment.
