Freeze‐Casting Enabled 3‐1 Types Porous PZNNT Ceramics for Energy Harvesting

Porous piezoelectric ceramics have attracted extensive attentions owning to their high piezoelectric energy harvesting figure of merit ( FOM 33 ), whereas PZNNT porous ceramics remain much less explored. In this work, 3‐1 type of pores along the freezing direction in PZNNT porous ceramics were successfully fabricated by freeze‐casting. The result indicates that the compressive strength, relative permittivity, and the piezoelectric constant of PZNNT porous ceramics increased with increasing solid content. The maximum FOM 33 of 51.27 pm 2 /N and piezoelectric voltage coefficient ( g 33 ) of 331.4 × 10 −3 Vm/N for PZNNT porous ceramics were obtained, which are superior to those of the vast majority of reported PZT‐based ceramics. This study suggested that introducing an air phase into PZNNT ceramics is beneficial for energy‐harvesting applications in wireless sensor networks.