Integration of a soft dielectric composite into a cantilever beam for mechanical energy harvesting, comparison between capacitive and triboelectric transducers

Abstract

Flexible dielectrics that harvest mechanical energy via electrostatic effects are excellent candidates as power sources for wearable electronics or autonomous sensors. The integration of a soft dielectric composite (polydimethylsiloxane PDMS-carbon black CB) into two mechanical energy harvesters is here presented. Both are based on a similar cantilever beam but work on different harvesting principles: variable capacitor and triboelectricity. We show that without an external bias the triboelectric beam harvests a net density power of 0.3 $$\upmu \mathrm{W}/{\mathrm{cm}}^{2}$$ μ W / cm 2 under a sinusoidal acceleration of 3.9g at 40 Hz. In a variable capacitor configuration, a bias of 0.15 $$\mathrm{V}/\upmu \mathrm{m}$$ V / μ m is required to get the same energy harvesting performance under the same working conditions. As variable capacitors’ harvesting performance are quadratically dependent on the applied bias, increasing the bias allows the system to harvest energy much more efficiently than the triboelectric one. The present results make CB/PDMS composites promising for autonomous portable multifunctional systems and intelligent sensors.

Fluidics for energy harvesting: from nano to milli scales

“…), mechanical energy (vibrations, wind, rain, etc. ) and salted gradient are the second main environmental source of energy 1–4 The mixing of 1 cm 3 of sea water with 1 cm 3 of river water produces an energy of 1.4 J. 5 The energy of a rainwater drop falling on a surface is of the order of magnitude of 10 μJ (speed of the drops estimated to 1 m s −1 ).…”

“…The results, although preliminary, are comparable to those obtained with piezoelectric 223 or capacitive systems. 2,224 If such systems are proved to work over several cycles, this approach is surely a path for the commercial development of the blue energy. The infrastructure costs are much lower in these miniature devices than those involved in producing energy.…”

A Hybrid Structure of Piezoelectric Fibers and Soft Materials as a Smart Floatable Open-Water Wave Energy Converter

“…Rodrigues et al achieved a maximum power output of 230 µW by placing four of their TENG modules on a 1:8 scale commercial buoy, equivalent to less than 2.26 mW/m 2 and 6.02 mW/m 3 if converted to energy per unit area and volume [ 58 ]. An energy harvester based on an electrostatic capacitive transducer, developed by Pruvost et al, produced a power output of 1.7 µW, equal to 0.24 µW/cm 2 and 4.53 µW/m 3 [ 59 ]. Taking into account the dimensions of these OWECs, the power generation from the OWEC developed in this study is more efficient than or comparable to those of in the above studies.…”