Realization of high-energy density polycrystalline piezoelectric ceramics

This letter reports a high energy density piezoelectric material in the system given as: Pb[(Zr0.52Ti0.48)O3]1−x[(Zn1∕3Nb2∕3)O3]x+yMnCO3, where x=0.1 and y varies from 0.5to0.9wt%. A piezoelectric material with high energy density is characterized by a high product of piezoelectric voltage constant (g) and piezoelectric strain constant (d). The condition for obtaining large magnitude of g constant was derived to be as ∣d∣=εn, where ε is the permittivity of the material and n is constant having lower bound of 0.5. It was found that for all practical polycrystalline piezoelectric ceramic materials the magnitude of n lies in the range of 1.1–1.30 and as the magnitude of n decreases towards unity a giant enhancement in the magnitude of g was obtained. A two step sintering process was developed to optimize a polycrystalline ceramic composition with low magnitude of n. For the optimized composition the value of g33 and d33 was found to be 55.56×10−3m2∕C and 291×10−12C∕N, respectively, yielding the magnitude product d33∙g33 as ∼16168×10−15m2∕N which is significantly higher than the reported values in literature. The magnitude of n for this composition was calculated to be 1.151. This material is extremely promising for immediate applications in the sensing and energy harvesting.