Scientists take the first step towards creating electrolyte-free batteries
Scientists from Peter the Great St. Petersburg Polytechnic University, together with their French, Swiss and Polish colleagues, managed to record unexpected phenomena in the crystal lattice of lead zirconate antiferroelectric. This discovery is the first step towards the creation of electrolyte-free batteries.
During the experiment, the scientists sought to understand the microscopic physics of one of the most difficult for theoretical description of antiferroelectrics, a model object of this group – lead zirconate. The properties of this crystal are the most representative in this group, and having studied them, the information obtained can be extended to the properties of a fairly large range of materials. This is necessary to create functional smart materials, that is, materials with predefined properties.
PbZrO3 crystals under the influence of external factors can have two types of crystal lattice ordering, for which the dipoles caused by displacements of positive lead ions are aligned parallel or antiparallel to each other. The functional properties of the material depend on what type of ordering will be chosen.
To analyze the emerging properties, it is necessary to understand how the structure of the material responds to changes in external parameters, such as temperature, pressure, and field. During the experiment, the research team tested how the material is affected by simultaneous changes in temperature and pressure.
To analyze the crystal structure, synchrotron radiation scattering by an ESRF source (European Synchrotron Radiation Facility) was used. It is the synchrotron source that is necessary to provide a strong flux of photons, with the help of which it becomes possible to study not only Bragg, but also diffuse scattering (scattering “between” Bragg reflections). It is due to diffuse scattering that it was possible to detect unknown processes occurring in the structure of the crystal.
Researchers have discovered two new crystalline phases at high temperatures and pressures.
Such conditions are close to those that can be created in promising energy storage devices (batteries), in which energy storage and release occurs due to switching between crystalline phases of various structures. Such structural switching will allow the release of significant amounts of energy in very short periods of time, and the absence of electrolytes has obvious advantages in terms of ease of integration and miniaturization of energy storage elements.
In the course of the study, scientists managed to fix a very rare phenomenon in the crystal structure of dielectrics – the formation of an incommensurate phase. This object in science is rather difficult to describe theoretically. SPbPU scientists together with their colleagues found out that lead zirconate is just such a functional material in which disproportionate phases are re
alized. “Based on macroscopic measurements, the researchers suspected that the existing theories describing the crystal lattice required revision,” explained R.G. … Burkovsky, Associate Professor of the Department of Physical Electronics, Institute of Physics, Nanotechnology and Telecommunications, SPbPU, the first author of the article. – There were contradictions when changing temperature and pressure, in connection with which we wanted to find out what processes occur at the micro levels. So, in the course of the experiment, we first identified an incommensurate phase in a pure antiferroelectric. “
Now the scientific community is faced with the task of constructing theoretical models that consistently describe the energy states in the crystal lattice and their response to external influence
s. “We have proven that such states exist in the crystal lattice, thereby setting a task for the scientific community, by solving which we will make a big step in the description of functional materials, ”Roman Burkovsky is sure.
Researchers’ article “Incommensurate phases in functional materials. Critical scattering and incommensurate phase transitions ”is published in the highly rated international journal“ Scientific Reports ”of the Nature group.
Distribution of diffuse scattering of X-ray radiation in the new phase of PbZrO3. The top and bottom rows correspond to different domain configurations
Source: SPbPU Media Center