Giant Piezoelectric Coefficients in Relaxor Piezoelectric Ceramic PNN-PZT for Vibration Energy Harvesting

It is well known that the piezoelectric performance of ferroelectric Pb(Zr,Ti)O-3 (PZT) based ceramics is far inferior to that of ferroelectric single crystals due to ceramics' polycrystalline nature. Herein, it is reported that piezoelectric stress coefficient e(33)= 39.24 C m(-2) (induced electric displacement under applied strain) in the relaxor piezoelectric ceramic 0.55Pb(Ni1/3Nb2/3)O-3-0.135PbZrO(3)-0.315PbTiO(3) (PNN-PZT) prepared by the solid state reaction method exhibits the highest value among various reported ferroelectric ceramic and single crystal materials. In addition, its piezoelectric coefficient d(33)*= 1753 pm V-1 is also comparable with that of the commercial Pb(Mg1/3Nb2/3)O-3-PbTiO3 (PMN-PT) piezoelectric single crystal. The PNN-PZT ceramic is then assembled into a cymbal energy harvester. Notably, its maximum output current at the acceleration of 3.5 g is 2.5 mA(pp), which is four times of the PMN-PT single crystal due to the large piezoelectric e(33) constants; while the maximum output power is 14.0 mW, which is almost the same as the PMN-PT single crystal harvester. The theoretical analysis on force-induced power output is also presented, which indicates PNN-PZT ceramic has great potential for energy device application.