Novel materials have always been the key to facilitating significant advancements in established technologies and enabling new functionalities, which is one of the reasons why entire ages of human development were named after the materials that defined them. Here, improved understanding the of the controlling mechanisms is central to engineering materials and developing new material systems, as it allows for extrapolation from existing knowledge to untested areas. The traditional system of experimental materials development is generally based on recognition of a pattern by the researcher through previous studies that results in the identification of a material of interest, synthesis of that material, characterization at the length scales of interest, and finally data analysis. Based on this new information and previous experience, a subsequent decision is made about the next possible material of interest, thereby acting as a feedback loop. There has been a significant interest in accelerating this traditional system using various technologies, including high-throughput synthesis and characterization techniques. Here, artificial intelligence methods have been developed and significantly advanced to aid in automated decision-making. Despite this, accelerated experimental methods haven’t been successfully deployed in all areas of material development to keep pace with advances in computations and machine learning. One such area is in ceramics processing using solid-state reaction method with dry powders, which is central to numerous industrial ceramics applications. As such, this contribution presents the development of a semi-autonomous system based on a high-precision powder dosing robot for the synthesis and structural characterization of up to approximately 100 polycrystalline ceramic samples per day using the solid-state reaction method. Recent data on the processing of lead-free ferroelectric BF-BT and characterization of the crystal structure across the full compositional range is presented as an example study. Here, opportunities and limitations of high-throughput processing will be discussed.

The wide use of Pb-based piezoceramics in research and industry raises environmental concerns. Yet, a proper recycling route for reusing the hazardous element is lacking. This research demonstrates a potential method for recycling broken piezoceramics by constructing upside-down composites between oxide and halide perovskites. A non-piezoelectric halide perovskite composition, C6H5N(CH3)3CdCl3, and a piezoelectric counterpart, (CH3)3NCH2ClCdCl3, are used as binders. The binder coats the piezoceramic fillers which are then hot pressed at mildly elevated temperatures under ultrahigh pressures. The halide perovskite binders are able to create intergranular interfaces among densely packed oxide perovskite fillers, thanks to their excellent wettability on surface of oxide perovskite particles as well as the low-temperature crystallization. The aging effect of dielectric and piezoelectric properties caused by the instability of halide perovskites is also studied. Optimum piezoelectric charge coefficient (d33) values of 90 and 116 pC N−1 and piezoelectric voltage coefficient (g33) values of 37 and 29 mVm N-1 are obtained from the recycled materials with the two types of halide perovskite binders, respectively. The g values are comparable to those of several high-quality piezoelectric ceramics, establishing the demonstrated method towards an energy-efficient process for producing recycled and reusable piezoelectric materials and thus providing a sustainable solution to issues of hazardous elements in waste piezoelectric components.

Among the routes toward sustainable production of piezoelectric materials, the upside-down composite method has recently made advances towards the recycling of retired and/or discarded piezoelectric components for a second life in sensor applications with negligible energy consumption compared to the conventional solid-state as well as the cold sintering routes. However, the drawback of this recycling method is that the retired/discarded piezoelectric material is crushed and pressed into composites as discrete filler particles embedded in a suitable matrix/binder, resulting in only about 10% retention of the piezoelectric charge coefficient (d). The inferior d values in the upside-down composites, as is the case in any ordinary piezocomposite, is attributed to the disparate permittivity values between the filler and binder. This permittivity difference forces most of the poling electric field to concentrate on the low permittivity and non-piezoelectric binder. This work explains this phenomenon specifically in upside-down composites by combining empirical evidence and modelling using three different sets of lead-based and lead-free fillers having similar d values but different permittivity values. This study also extends the methodology from the upside-down binder volume fraction range towards that of ordinary piezocomposites and thus fills the gap of existing knowledge between these two types of composites. By properly adjusting modelling parameters, the resultant piezoelectric property in the upside-down composites can then be predicted given a specific filler, binder, and their respective volume fractions. The multi-variable study contributes to the scaling up and optimization of piezoelectric properties for the upside-down composite method to be used for recycling piezoceramics.