Large Piezoelectricity and high Power Density of 3D Printed-Multilayer Copolymer in Rugby Ball Structured Mechanical Energy Harvester

Piezoelectric polymers are featured with flexible, easy processing into any shapes, however, their piezoelectric coefficients such as d33 are quite low (~24 pC N-1). Here we report 3D printed multilayer β-phase PVDF-TrFE copolymer without high temperature annealing and complicated transfer processes exhibiting much higher effective piezoelectric coefficient d33 (~ 130 pC N-1 for six 10 μm-layers). In order to confirm its high power density as well, a rugby ball shape energy harvester using the multilayer copolymer and operating in flextensional mechanism is prepared. The experimental results show that it can produce the peak voltage and current of ~88.62 Vpp and 353 μA, respectively, which are 2.2 and 10 times of a single-layer PVDF-TrFE harvester, under a pressure of 0.046 MPa. Notably, its peak output power density is as high as 16.4 mW cm-2 (according to P_peak=(V_peak I_short)/2); while at the load of 568 kΩ, it is still 5.81 mW cm-2. The proposed copolymer processing method and flextensional mechanism in a rugby ball configuration show the great potential for future micro energy development in flexible, wearable electronic devices and wireless sensor network.