Pyroelectric waste heat energy harvesting using the Olsen cycle on Pb(Zr, Ti)O3-Pb(Ni, Nb)O3 ceramics

This paper is concerned with direct energy conversion of waste heat into electrical energy by performing the Olsen cycle on lead nickel niobate zirconate titanate (PNNZT) pyroelectric ceramics undergoing a relaxor-ferroelectric phase transition. First, isothermal bipolar displacement vs. electric field hysteresis loops were measured for different temperatures and electric field spans. The Curie temperature varied between 150 °C and 240 °C as the electric field increased from zero up to 3 MV/m. The energy and power densities of the Olsen cycle on PNNZT were measured by cycling the specimens over a wide range of temperatures, electric fields, and frequencies. A maximum energy density of 1417 J/L/cycle was recorded with 200 μm thick PNNZT cycled at 0.033 Hz between temperatures 20 °C and 240 °C and electric fields 0.3 MV/m and 9.0 MV/m. To the best of our knowledge, this is the largest energy density ever obtained experimentally for any pyroelectric material. In addition, a maximum power density of 78 W/L was measured by cycling the material temperature between 20 °C and 220 °C and applying the electric field between 0.3 MV/m and 9.0 MV/m at 0.09 Hz.