Phd students of the FTiMS faculty received financing for research projects from the national science center | Gdańsk University of Technology

Małgorzata Nadolska, PhD student of our Faculty, has received funding  from the National Science Center in frame of PRELUDIUM programme. Her research project entitled “Ammonium vanadate/rGO composites: synthesis, physicochemical characterization and electrochemical properties” will last 2 years and the granted funds are 129 000 PLN!

The aim of the project is synthesis and investigation of composite materials based on ammonium vanadium oxides (AVOs) and reduced graphene oxide (rGO). AVOs possess specific layered structure which, together with multivalent nature of vanadium, make them potential candidates for cathode material in rechargeable ion batteries.

“However, their application is limited by low electrical conductivity and poor structural stability- says the originator- On the other hand, carbon-based composites (including rGO-based composites) have been successfully employed in various kinds of electrochemical devices. It is expected that the combination of rGO (with high electrical conductivity and large accessible surface area) with AVOs will result in excellent electrochemical properties. Moreover, hierarchical composite architecture should ensure structure integrity, providing long-term cycling stability.”

Figure: Conception of the proposed project.

Composites will be obtained by facile one-pot hydrothermal method under variable synthesis conditions (e.i. time, temperature, initial pressure and precursor solution composition). Mild conditions, such as relatively low temperatures (below 200°C), short time (few hours) and water as a reaction medium, together with low-cost chemicals make the proposed synthesis very attractive. Obtained AVO/rGO composites will be fully characterized in order to determine their crystal structure, chemical composition and morphology. This will allow to evaluate the influence of synthesis parameters on the final product for the first time, which is important in designing novel materials for further applications. Finally, composites will be testes as a new cathode material for rechargeable mono and multivalent-ion batteries.

Research project prepared by Bartosz Trawiński MSc, a doctoral student at the Institute of Nanotechnology and Materials Science, received funding from the National Science Center under the Preludium programme. The title of the project is "Ionic thermoelectric phenomena in copper(I) selenide during the α→β phase transition and beyond". The research will be carried out for 2 years, and the allocated funds are almost PLN 140,000!

“Thermoelectric phenomena related to ions is a poorly understood part of the knowledge of thermoelectric materials. - says Mr Trawiński - One of such materials is copper selenide (Cu2Se). Particularly interesting are the properties of Cu2Se during the phase transition, which takes place around 140 ° C. In this transformation, the material changes its structure so that the copper ions are "released" and the material becomes an ionic conductor. The study of thermoelectric phenomena during this transformation is the goal of the project. "
The subject of the project, however, is not limited to one material: "In addition to the study of copper selenide itself, non-stoichiometric materials with a Cu to Se ratio of less than 2 will be investigated. Copper selenide can be doped, e.g. by changing some selenium atoms with tellurium and some copper atoms silver or indium. It is known that such changes in composition affect the transport of copper ions in copper selenide and thus the thermoelectric effect. " - adds the future project manager.
The key point of the funded project will be to adapt the measurement technology to measure ionic, not electronic properties. In devices for measuring electrical properties, electron-conducting metal parts are typically used. This makes the apparatus sensitive to properties related to electrons. To measure the ionic properties, it is necessary to develop an apparatus with electrodes conducting only copper ions. An additional difficulty will be the small number of materials that can be used for the electrodes operating at temperatures as low as 100 ° C. In addition to the thermoelectric effect, the course of the phase transition will be analyzed by means of thermal analysis and evaluation of the crystal structure. The comparison of these results will allow concluding on the phenomena occurring during the transformation.
Project manager's biography:
The future project manager, Bartosz Trawiński MSc, a 4th-year doctoral student of the PhD Studies in Physics at the Faculty of Applied Physics and Mathematics. He conducts his research work at the Institute of Nanotechnology and Materials Science. His doctoral thesis will concern the process of producing thermoelectric materials by the method of oxides’ reduction. He also studies the thermoelectric properties of various materials.