High energy efficiency nanodielectrics with relaxor ferroelectric polymer and antiferroelectric (Pb_0.97La_0.02) (Zr_0.63Sn_0.3Ti_0.07)O₃ ceramics

Dielectric materials with high-energy-density and low-energy-loss have received lot of attention in terms of renewable energy storage and application. PVDF-based polymer/ceramics composite dielectrics are considered as one of the most promising materials due to their high dielectric constant. However, the high remnant polarisation (P_r) of ferroelectric polymer matrix and ceramics fillers generates a lot of energy loss and residual heat during charge-discharge cycles, which limits their practical applications. Compared with ferroelectrics, relaxor ferroelectric and antiferroelectric dielectrics may have high energy efficiency due to their lower P_r. Here, the relaxor ferroelectric matrix and antiferroelectric filler coated by the polydopamine layer were prepared by chemical grafting and solid-state method, respectively. Afterwards, the P(VDF-TrFE-CTFE)-g-PMMA/PLZST nanocomposite was prepared via solution casting. Experimental results show that the energy loss of the optimised nanocomposites was significantly reduced, leading to an enhanced charge-discharge efficiency (η) of 78% at 450 MV/m, which is 267% of the pure P(VDF-TrFE-CTFE) matrix and superior to those of most polymer/ferroelectric filler nanocomposites. It is encouraging that the breakdown strength and energy storage density of the P(VDF-TrFE-CTFE)-g-PMMA/PLZST nanocomposites with 6 wt% filler fractions reach the values of 458 MV/m and 10.3 J/cm³. This study establishes a simple and effective strategy for preparing capacitors with high energy efficiency.