Study on recycling of lead-based piezoceramics using trimethylchloromethyl ammonium-based halide perovskite binder

Oxide-halide perovskite upside-down composites have been demonstrated for recycling heavy-eco-footprint piezoceramics. However, options for the binders are limited. As the binder significantly affects the electrical properties of the recycled materials, the available binder material pool needs to be expanded. This work explores the use of a halide perovskite compound, Me₃NCH₂ClCdCl₃ (TMCM-CdCl₃), as the binder to study the interplay between the filler's and binder's characteristics and its influence on electrical properties of the recycled piezoceramics. Two Pb-containing ceramic fillers, Pb(Zr,Ti)O₃ and Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃, which possess distinct permittivity and Curie temperatures, are used in the study. A wide range of fabrication temperatures span the fillers’ and binder's phase transition and decomposition regions are involved. Results suggest that a coincidence of the filler's ferroelectric-paraelectric phase transition with the binder's decomposition during fabrication can significantly degrade the composite's electrical properties due to the microstructural frustration among porosity increase, densification lag, and enlarged filler-binder permittivity mismatch. This work has achieved the champion relative permittivity of ∼600 at 1 kHz and comparable piezoelectric responses (charge and voltage coefficients of ∼90 pC N⁻¹ and 31-32 mVm N⁻¹, respectively) among all the known upside-down composites. These results advance the understanding of structure-property correlations in upside-down composites.