ИСТИНА

разработка и изучение композитных материалов для создания долговечных и недорогих НИА на основе распространенных элементов (C, Na, P, Mn, Fe, Ti, V…) для стационарного хранения энергии.

The need of human society for reliable, efficient and inexpensive ways to store electricity is growing every year. The systems most in demand today are lead-acid batteries (LABs) and lithium-ion batteries (LIBs). At the same time, on the one hand, there is a clear tendency to replace the LAB technology with more modern and constantly cheaper LIBs, and on the other hand, limited lithium resources can become “new oil” with a strong dependence of energy costs on raw material suppliers and the end devices themselves. The use of sodium instead of lithium solves the problem of uneven distribution of resources and, in the long run, makes the technology even cheaper, which will allow it to quickly absorb the still huge LABs market. The development of scientific approaches for the production of materials and batteries will reduce dependence on imports of lithium resources and will reduce the cost of devices for end users. The obviousness of these trends for the entire world community has led to the fact that almost all scientific groups that were previously involved in the development of materials/electrolytes/technologies for LIBs have focused their efforts on finding ways to solve the problems of SIBs. These problems concern all the main components of SIB - cathode, anode and electrolyte, therefore improved cathode and anode materials (as well as scalable methods for their synthesis) are currently being developed, which, in combination with functional electrolytes, are capable of providing long-term cycling of full electrochemical cells. The cycle stability of SIBs is related to irreversible phase transition in the bulk structure, surface reactions, mechanical fracture of particles and electrodes as well as decomposition of other cell components at high voltages during large-sized Na+ (de)intercalation. The air-stable and high-capacity electrodes are significant for SIBs. Layered cathode materials NaxMO2 (0<x≤1, M represents transitional metal) are attractive due to its high capacity but suffer from air instability. Polyanion compounds (phosphates, pyrophosphates, etc.) are extensively investigated due to its stability but with low electron conductivity and capacity. On the anode side, the tap density and initial Coulombic efficiency of hard carbon are insufficient. Investigation on both of the cathode and anode is of high importance for the development of SIBs. One of the most effective ways to combine the advantages of different types of materials (with the maximum suppression of their disadvantages) is the creation of composites. Aiming to build low-cost, long-lifespan and high-energy-density SIBs (≥160 Wh kg −1), this joint project will explore composite electrode materials for SIBs based on abundant elements (C, Na, P, Mn, Fe). The research will be focused on: 1) Synthesis of high-voltage and capacity cathode aNa(Fe,Mn,M)O2@(1-a)β-Na(V,M)P2O7 (0a1, M is transition element) – Russian side; (2) Investigation of Bi@C negative electrode with high tap density and its interface – Chinese side; (3) Operando, in situ and ex situ characterization for mechanism research – cooperative work; (4) Development of 10 Ah pouch cells - cooperative work. This project will contribute to elucidate the capacity degradation mechanism, carriers transport dynamics and surface/interface evolution behavior, and enclose the relationship between the structure and composition with electrochemical performance in multiple dimensions. Particular attention will be paid to studying the properties of the most promising objects at low temperatures (down to -40°C), as well as creating electrolyte solutions that provide optimal values of electrical conductivity and charge transfer resistance at the electrode-electrolyte interface.

1. Будут разработаны катодные материалы с оптимизированной структурой, морфологией и составом для создания натрий-ионных аккумуляторов, характеризующихся низкой стоимостью, высокой емкостью, повышенной безопасностью и длительным сроком службы. Ожидаются следующие характеристики: удельная емкость ≥ 150 мАч/г, срок службы ≥ 3000 циклов (сохранение емкости при циклировании током 1C ≥80%); 2. Будут разработаны анодные материалы для натрий-ионных аккумуляторов на основе композита Bi@C и изучено их поведение в различных электролитах. Ожидаются следующие характеристики: удельная емкость ≥ 350 мАч/г, срок службы ≥ 3000 циклов (сохранение емкости при циклировании током 1C ≥80%); 3. Будут приготовлены и охарактеризованы электролиты для для натрий-ионных аккумуляторов, позволяющие сохранять большую часть электрохимической емкости ячеек (не менее 50%) при понижении температуры разряда вплоть до -40оС. Также будут рассмотрены вопросы заряда НИА при пониженных температурах 4. С помощью operando, in situ и ex situ методов анализа будет проведено изучение фазовых и структурных превращений, валентных переходов, дефектообразования при (де)интеркаляции Na+ в катодные и анодные материалы как в ходе заряда-разряда, так и после длительного циклирования в полу- и полных ячейках; 5. Будут изготовлены прототипы натрий-ионных аккумуляторов емкостью 10 А•ч на основе вышеупомянутых электродных материалов. Ожидаемые характеристики: циклируемость более 2000 циклов, удельная энергоемкость ≥160 Вт•ч/кг.