Ultrahigh energy harvesting properties in Ag decorated potassium-sodium niobite particle-polymer composite

Composite-type piezoelectric nanogenerator (PENG) can potentially provide power to the flexible electronics devices by harvesting the mechanical energy. The electricity output of the PENG is not entirely excavated until now because the polarization dipoles are not sufficiently aligned during the high-voltage poling process. In this study, some Ag particles are attached on the (K0.4425Na0.52Li0.0375) (Nb0.86Ta0.06Sb0.08)O3 (KNN) piezoelectric particles and then they are mixed with multi-walled carbon nanotubes and polydimethylsiloxane to fabricate the PENG device. The Ag particles can reduce the optimal poling electric field from 10 kV/mm down to 5 kV/mm. The PENG device with Ag particles poled at 5 kV/mm can generate the highest open-circuit voltage of 282 V, short-circuit voltage of 32.2 μA, and maximum instantaneous power of 3.5 mW under the external mechanical stress of 10 kPa without time-dependent degradation (only 27.9 V and 2.6 μA for the pure KNN-based PENG poled at 10 kV/mm). These are much better than previously reported composite-type PENG. The electrical energy generated from the PENG (20 mm × 40 mm) can light up 40 white light emitting diodes instantaneously without any storage unit during the stomping stage.