Harnessing low frequency-based energy using a K0.5Na0.5NbO3 (KNN) pigmented piezoelectric paint system

Abstract

A new approach for harnessing low-frequency energy using a piezoelectric paint system was developed using potassium sodium niobate (K_0.5Na_0.5NbO₃, ‘KNN’) as a pigment in an alkyd resin binder. The highly crystalline, rectangular-shaped KNN pigment nanoparticles with an orthorhombic phase acts as a piezoelectric material and determines the functional properties of the paint system. The energy-harvesting ability of the as-developed paint system was evaluated using a cantilever beam test in which the vibration of the beam was measured as the direct output from the piezoelectric paint. The layered conductive copper beryllium cantilever/piezoelectric paint/aluminium acts as a device structure to obtain the electrical responses of the cantilever on various mass loadings (7.2 g, 14.4 g and 21.6 g). The resonant frequency (f₀) of the vibrating cantilever showed a decreasing trend as the proof mass loading increased. A maximum open circuit voltage of 1.4 V was produced by the piezoelectric paint coated on the surface of the deflecting cantilever beam at a proof mass (m_p) of 21.6 g. This suggests that the developed lead-free piezoelectric paint was capable of harvesting energy from the vibrating source and was also sensitive to the degree of mechanical strain exerted by the deflecting cantilever beam.