Abstract Limited by the inherent properties of being difficult to be polarized due to its high resistance, PVDF bulk material with high β-phase content is hard to obtain by conventional… Click to show full abstract
Abstract Limited by the inherent properties of being difficult to be polarized due to its high resistance, PVDF bulk material with high β-phase content is hard to obtain by conventional methods which are suitable for membrane material. Herein, a novel strategy is proposed for the mass production of high-performance β-PVDF-based piezoelectric and triboelectric hybrid nanogenerator (PTNG) employing large-scale PVDF films or bulks by using liquid nitrogen to induce a phase transition and in-situ doped conductive polyaniline (PANI). Polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) with high piezoelectric coefficient, filled with PANI as a conductive material and sodium carboxymethyl cellulose (SCMC) for increasing porosity, is hot pressed to obtain a composite piezoelectric polymer for PTNG. The subsequent “quenching” process of the piezoelectric polymer allows its high content of β-phase, which in turn makes the PTNG exhibit excellent piezoelectric properties. The optimal output of the PTNG, with a β-phase content of up to 71%, reaches 246 V and 122 μA at the frequency of 30 Hz and pressure of 0.31 MPa, and the power density is calculated to be 6.69 W/m2. Moreover, the PTNG can directly light up 119 blue light-emitting diodes (LEDs) with a size of 3 mm in series. The excellent performance verifies the reliability and accuracy of the method, that is, the β-phase transformation of disordered amorphous PVDF occurs at low temperature and high-rate quenching, and PANI opens the channel for carriers to move charge in the bulk material. This innovative method presented here is a simple and efficient approach for preparation of bulks with high β-phase and low internal resistance, which undoubtedly provides a feasible direction for the industrialization of high-performance PENGs.
               
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