Intergranular Particle Bridge Structure Design Strategy Boosts High-Temperature Energy Harvesting Performance of Fine-Grained Ceramics

The piezoelectric energy harvester (PEH) for self-powered high-temperature microsensors puts forward an urgent need for high-temperature fine-grained piezoceramics with a high piezoelectric charge coefficient (d33), which is still a huge challenge for material design. This study proposes a design strategy for building an intergranular particle bridge (IPB) structure, which solves the bottleneck in high-temperature piezoceramics, that is, difficulty in obtaining both a dense and fine-grained structure together with high d33. The IPB has a dual function, that is, inhibiting the migration of the grain boundary during the densification process to achieve a fine-grained structure and assisting in the construction of hierarchical nanodomain patterns to increase the d33. Using partially amorphous nanopowders as the precursors, the 0.345BiScO3–0.615PbTiO3–0.04Pb(In1/2Nb1/2)O3 piezoceramics with an IPB structure prepared by pressureless sintering technology have an average grain size of only 0.26 μm and the d33 is as high as 343 pC/N, which is significantly better than the previous works. More importantly, the PEH made of optimized materials has an excellent power generation capacity at a high temperature of 250 °C, showing important application prospects in driving high-temperature microsensors. The design strategy proposed in this work can provide a reference for the preparation of more high-performance fine-grained piezoceramics.