Defense of the dissertation of Yerdauletov Meir Sapargalievich for the degree of Doctor of Philosophy (PhD) in the educational program «8D05305 - Nuclear physics»

L.N. Gumilyov Eurasian National University, a dissertation defense for the degree of Doctor of Philosophy (PhD) by Yerdauletov Meir Sapargalievich on the topic «Investigation of the effect of the microstructure of positive electrodes of chemical current sources on their functional characteristics» in the educational program «8D05305 – Nuclear physics».

The dissertation was carried out at the Department of «Nuclear Physics, New Materials and Technologies» of L.N. Gumilyov Eurasian National University.

The language of defense is russian

Official reviewers:

Askaruly Kydyr – PhD, Associate Professor at the A. Burkitbayev Institute of Energy and Mechanical Engineering of K.I. Satpayev Kazakh National Research Technical University, (Almaty, Republic of Kazakhstan);

Belgibayeva Ayaulym Didarbekkyzy – PhD, Leading Researcher, Acting Head of the Laboratory of Energy Storage Systems "National laboratory", Nazarbayev University, Astana, (Republic of Kazakhstan).

Temporary members of the Dissertation Council:

Kopishev Eldar Yertayevich – Candidate of Chemical Sciences, Head of the Department of Chemistry of the Eurasian National University, (Astana, Republic of Kazakhstan);

Malchick Fyodor Igorevich – PhD, Associate Professor, Head of the Laboratory of Electrochemical Production Technologies of Al-Farabi Kazakh National University, (Almaty, Republic of Kazakhstan);

Ahmadov Gadir Sattar oglu – PhD, Department of Nuclear Research, Innovation and Digital Development Agency, (Baku, Republic of Azerbaijan).

Scientific consultants:

Daniyar Maralovich Janseitov – PhD, Leading Researcher at the RSE “Institute of Nuclear Physics” (specialty "6D060500 – Nuclear Physics"), (Almaty, Republic of Kazakhstan);

Avdeev Mikhail Vasilyevich – Doctor of Physical and Mathematical Sciences, Professor, Head of the Sector of the I.M. Frank Neutron Physics Laboratory of the Joint Institute for Nuclear Research, (Dubna, Russian Federation).

The defense will take place on January 24, 2025, at 02:00 PM in the Dissertation Council for the training direction «8D053 – Physical and chemical sciences» in the educational program «8D05305 – Nuclear physics» of L.N. Gumilyov Eurasian National University. Conducting a meeting of the dissertation council in a mixed (offline and online) format.

Link: https://clck.ru/3FAWUu

Address: Astana, Satpayev St. 2, room 302

Abstract (English): The dissertation work of Yerdauletov Meir Sapargalievich "Investigation of the effect of the microstructure of positive electrodes of chemical current sources on their functional characteristics", submitted for the degree of Doctor of Philosophy (PhD) according to the educational program: 8D05305 – "Nuclear Physics" This dissertation work presents the results of research carried out with the aim of conducting systematic studies of qualitative and quantitative patterns between the microstructure of electrode coatings and their specific characteristics. Information about the microstructure of coatings was obtained using small-angle thermal neutron scattering, which, due to the high penetrating power of this radiation, makes it possible to study industrial systems within the framework of non-destructive testing. Fundamentally new scientific and technical solutions for the formation of effective electrodes are based on the use of nanostructured conductive additives based on graphene derivatives and modified carbon nanotubes, as well as on the use of polymer binders with different structures. The results were obtained at the low-angle neutron scattering facility at the research reactor IBR-2 LNF JINR. The influence of nanostructured carbon additives on the functional characteristics of chemical current sources has been evaluated. The paper also presents the results of the development of a prototype lithium-ion battery with increased specific characteristics. Scientific problem. A scientific problem. The limited supply of fossil energy sources, as well as the widespread deterioration of the environmental situation, leads to the need to increase the share of renewable energy consumption and to the inevitable use of electric drives for vehicles. The widespread use of renewable energy sources and electric vehicles is limited by the lack of high-capacity and energy-efficient energy storage devices, among which rechargeable chemical current sources (HIT) occupy an important place. In the field of "green" energy, HIT is necessary to equalize the load in electric networks, regulate frequency and provide consumers with renewable energy at times of power generation failures arising from the use of wind, solar or wave power plants. In this regard, an urgent task is to improve existing approaches, as well as the search and development of new energy-intensive and efficient rechargeable batteries. On the one hand, an increase in the specific characteristics of lithium-ion batteries is associated with the development of new electrode materials that provide a higher reversible specific capacity, as well as a large potential difference and operate at higher discharge/charge currents. On the other hand, a significant gain in specific indicators can be achieved by optimizing the internal architecture of the battery, which is primarily determined by the microstructure of the applied electrode coatings. In addition, the most important component of the battery is the separator, which affects the internal resistance of the storage device and, as a result, the kinetics of lithium ion transfer during the charge-discharge process. The relevance of the work and the state of the scientific problem. The relevance of the work and the state of the scientific problem. Currently, lithium-ion batteries are the most commonly used chemical current sources. When considering the evolution of modern electronic devices, there is a clear trend towards their miniaturization and increased functionality. This leads to a significant increase in energy consumption, which, in turn, requires the creation of more efficient and compact energy sources (storage). The specific energy of lithium-ion batteries is determined by the specific characteristics of the electrode materials, and above all, the characteristics of the cathode material, because it accounts for about 40% of the mass of all active components. In addition, the battery contains inactive components such as current collectors, separators, packaging, etc., which are necessary for the battery to function. Therefore, the problem of increasing the energy efficiency of modern energy storage devices with restrictions imposed on the battery form factor, on the one hand, is related to the problem of obtaining and researching new active electrode materials. On the other hand, the influence of the microstructure of positive electrodes as well as conductive additives is important, and thereby contribute to an increase in the specific energy of the battery. The aim of dissertation work – The purpose of this dissertation work is to develop general practical criteria for optimizing the microstructure of electrodes based on a wide range of active materials, nanostructured carbon additives and modified polymer binders, allowing for significant gains in specific energy and power of lithium–ion batteries. Scientific and technological solutions developed during the implementation of the project for the formation of electrode coatings with a given microstructure can form the basis for prototyping and creating electrochemical energy storage devices with increased specific characteristics. Research task. 1. Investigation of the effect of the ratio between the active material and the conductive additive on the characteristics of the electrode; 2. Investigation of the effect of the microstructure of positive electrodes by small-angle neutron scattering; 3. Development of practical criteria for optimizing the microstructure of electrodes of active materials; 4. Creating a prototype based on all the data. Object of research. LFP, NCA, NMC, V2O5, LTO electrodes were selected as objects for research Subject of research. The subject of the study is the microstructural features inside electrode materials in chemical current sources, as well as the study of small-angle neutron scattering for their research and analysis The research methods. The technological aspects of manufacturing electrodes based on LFP, LTO, NMC, NCA and high-capacity composite materials using carbon nanotubes as conductive additives have been studied. As a result of the work, the relationship between the microstructure of electrodes (in particular, porosity, tortuosity of pores, type and content of an electrically conductive additive) and their specific characteristics using small-angle neutron scattering was studied. Statements for the defense: 1) The presence of an optimal content of carbon nanotubes in the electrodes with respect to capacitance is shown. Electrodes with 1% CNT demonstrate a higher specific capacity compared to electrodes containing 5-15% soot. At the same time, increasing the CNT content to 10% significantly reduces the volumetric capacity of the electrode, which becomes lower than that of electrodes with soot. 2) Based on measurements of small-angle neutron scattering, it is shown that the CNT grid embedded in the electrode layer provides its greater wettability with electrolyte compared to soot used as a standard conductive additive. This results in better electrode performance. 3) The influence of CNTs on the rheological properties of the electrode suspension in the manufacture of electrodes has been determined. In the manufacture of thick (thickness over 100 microns) electrode coatings, an increase in the mass content of CNTs over 5% significantly complicates the process of their dispersion in a solvent; the manufacture of appropriate homogeneous layers becomes problematic. 4) Electrodes were obtained from bio-waste as a promising electrode material in chemical current sources. 5) The practical applicability of the electrode technology in question was confirmed on a prototype cell with a obtained specific energy density of 150 W kg-1.40 Farad/g. Scientific novelty of the work. The work was aimed at conducting systematic studies of qualitative and quantitative patterns between the microstructure of electrode coatings and their specific characteristics. Information about the microstructure was obtained using small-angle thermal neutron scattering, which, due to the high penetrating power of this radiation, makes it possible to study industrial systems within the framework of non-destructive testing. Fundamentally new scientific and technical solutions for the formation of effective electrodes will be based on the use of nanostructured conductive additives based on graphene derivatives and modified carbon nanotubes, as well as on the use of polymer binders with different structures. The properties and applications of promising materials for lithium ion batteries, in particular from bio-waste such as rice husks, have been studied. Scientific and practical value of the work. The results obtained in the work of scientific and technological solutions for the formation of electrode coatings with a given microstructure can form the basis for prototyping and creating electrochemical energy storage devices with increased specific characteristics. This work is aimed at conducting systematic studies of qualitative and quantitative patterns between the microstructure of electrode coatings and their specific characteristics. Information about the microstructure of coatings was obtained using small-angle thermal neutron scattering, which, due to the high penetrating power of this radiation, makes it possible to study industrial systems within the framework of non-destructive testing. Fundamentally new scientific and technical solutions for the formation of effective electrodes are based on the use of nanostructured conductive additives based on graphene derivatives and modified carbon nanotubes, as well as on the use of polymer binders with different structures. Investigation of the structural features of electrode coatings and determination of their effect on electrochemical characteristics. A wide range of active materials is considered and a structural study of coatings containing various nanostructured conductive additives is carried out: standard carbon black, graphene derivatives, modified carbon nanotubes; cathode/anode materials, in particular from biowaste, will also vary. In turn, comparison with electrochemical measurements made it possible to establish a clear connection between the variation in the structure of electrode coatings and their specific energy storage characteristics at different charging/discharging capacities, and resistance to cycling. It is important to note that the results of the work will form a serious scientific and technical foundation for further advanced research in the field of developing new generation energy storage devices. Personal contribution of the author. The results presented in the dissertation were obtained by the author together with the staff of JINR (Dubna, Russian Federation), Dubna State University (Dubna, Russian Federation), reflected in joint publications. The author took a direct personal part in the formulation and conduct of experiments, the processing of experimental data and the interpretation of experimental results as a full member of the scientific group. The author made a huge contribution to the experiment at the small-angle neutron scattering facility and investigated the microstructure features of electrode coatings that have a clear connection with their electrochemical characteristics at the IBR-2 LNF reactor (JINR, Russia). At this installation, the author studied various samples of electrodes with different content of carbon additives using the example of carbon nanotubes (CNTs) and soot. Based on experimental data of small-angle neutron scattering, it is shown that the CNT grid embedded in the electrode layer provides its greater wettability with electrolyte compared with soot used as a standard conductive additive. This results in better electrode performance. Reliability of the results of the work The correctness of the experimental studies carried out and the reliability of the results obtained in the dissertation work are justified by the use of well-known and mastered methods. The experimental results obtained have been well analyzed and are consistent with the work of other researchers in this field. The main results of the dissertation have been published in peer-reviewed international scientific journals and presented in the materials of leading international conferences on neutron physics Approbation of work. The materials of the dissertation work were presented and reported at the following national and international conferences: 1) The International Scientific Conference of Young Scientists and Specialists (AYSS-2020), (April 15-19, 2020 JINR, OMUS, Dubna, Russia, JINR, Dubna, Russia) 2) International Conference «Condensed Matter Research» at the IBR-2 12.10.20, International Conference Hall, Dubna; 3) TURK-COSE 2020: 2. International Turkic World Congress on Science and Engineering 4) III International Scientific Forum “Nuclear Science and Technologies”, RSE "Institute of Nuclear Physics", Ministry of Energy of the Republic of Kazakhstan, Almaty, Kazakhstan, 20 – 24 September 2021 5) I Международной Школы-конференции «Атом. Наука. Технологии», 14-16 апреля, 2021, Институт ядерной физики, Алматы, Казахстан 6) КОНФЕРЕНЦИЯ ПО ИСПОЛЬЗОВАНИЮ РАССЕЯНИЯ НЕЙТРОНОВ В ИССЛЕДОВАНИИ КОНДЕНСИРОВАННЫХ СРЕД (РНИКС-2021), Екатеринбург, Россия 27 сентября – 1 октября 2021 7) I Международная Школа-конференция «Атом. Наука. Технологии», РГП ИЯФ МЭ РК, Алматы, Казахстан 14-16 апреля 2021 8) International Conference Condensed Matter Research at the IBR-2 25.04.22 9) JINR Association of Young Scientists and Specialists, Conference "Alushta-2022", AYSS,JINR, Alushta, Russia 10.06.2022 10) 55th meeting of the PAC for Condensed Matter Physics, FLNP, JINR, Dubna, Russia 2022 11) IV International Scientific Forum “Nuclear Science and Technologies”, RSE "Institute of Nuclear Physics", Almaty, Kazakhstan, 26 – 30 September 2022 12) ВСЕРОССИЙСКАЯ НАУЧНО-ПРАКТИЧЕСКАЯ КОНФЕРЕНЦИЯ «ЗАДАЧИ И МЕТОДЫ НЕЙТРОННЫХ ИССЛЕДОВАНИЙ КОНДЕНСИРОВАННЫХ СРЕД» 21-22 сентября 2023 13) 56th meeting of the PAC for Condensed Matter Physics, FLNP, JINR, Dubna, Russia 17-18 January 2023 Publications Based on the materials of the dissertation, 5 papers were published, of which 5 articles were published in a publication with a non-zero impact factor included in the Scopus and Web of science database. The structure and scope of the thesis. The dissertation consists of an introduction, four sections, a conclusion and a list of 95 references. The total volume of the work is 86 pages, including 6 tables and 48 figures. In the introduction he relevance of the research topic is substantiated, a brief literary review of the available data on the topic of the dissertation is given. The formulation of the scientific problem within which this work was carried out is given, the objectives of the work are formulated, the novelty of the results obtained, their scientific and practical value. The main provisions submitted for defense, the personal contribution of the author, the approbation and summary of the dissertation are given. The first section is devoted to an overview and theoretical foundations of the electrode materials being developed and used in chemical current sources. The main focus is on the principle of battery operation and the use of various cathode materials in the analysis of experimental data. In addition, detailed information is provided on the physical properties and crystal structures of cathode materials studied in the dissertation work. The second section is devoted to a detailed description of experimental methods, the development and application of which is aimed at this dissertation work. A detailed description of the microstructure of the samples and experimental data from the cathode material of vanadium oxide and carbon conductive additives is given. Experimental studies of the effect of various nanostructured carbon conductive additives on electrochemical data are also presented. The third section is devoted to the synthesis of obtaining promising electrode materials obtained from biomass. Experimental and methodological developments are presented to describe the microstructure and electrochemical data of the obtained samples. A comparative analysis with the electrochemical characteristics of other activated carbons obtained from various starting biomaterials for lithium-ion capacitors also showed that the material proposed in this work has excellent capacitive and cyclic properties. The fourth section is devoted to the analysis of microstructural features of electrodes. The results of a study on the porosity of filling pores with an electrolyte obtained using small-angle neutron scattering are presented. The efficiency of introducing graphene-based carbon additives into various types of electrode materials (LFP, LTO and NMC) for lithium-ion batteries with liquid electrolytes has been evaluated by the method of small-angle neutron scattering. The technological aspects of manufacturing a prototype based on LFP with high capacity using carbon nanotubes as conductive additives are studied in detail. In conclusion the main conclusions on all the results of the dissertation research are summarized.

Dissertation

List of Scientific Works

Consultant's Review

Foreign Consultant's Review

Conclusion of the Research Ethics Committee

Official Reviewer's Review

Official Reviewer's Review