From Lithium-Ion to Sodium-Ion Batteries

The research is mainly motivated by the abundance of sodium and the larger amount of sodium compounds in comparison with lithium

Збалансування інтересів сторін трудових відносин як засада забезпечення договірного регулювання таких відносин з боку держави

Стаття присвячена вивченню збалансування інтересів сторін трудових відносин не як мети договірного регулювання вказаних відносин, а як орієнтира та базисної засади для держави при розробці нового Трудового кодексу України. Визначається сутність такого принципу та його основна спрямованість. Ключові слова: сторони трудових відносин, регулювання трудових відносин, інтерес, договірне регулювання трудових відносин.Статья посвящена изучению сбалансирования интересов сторон трудовых отношений не как цели договорного регулирования указанных отношений, а как ориентира и базисного основания для государства при разработке нового Трудового кодекса Украины. Определяется сущность такого принципа и его основная направленность. Ключевые слова: стороны трудовых отношений, регулирование трудовых отношений, интерес, договорное регулирование трудовых отношений.The article is devoted to the analysis of balancing interests of labour relations parties as not as the purpose of contractual regulation the mentioned relations but as the guideline and basic priority for state with elaborating the new Labour code of Ukraine. The essence of this principle and its leading direction are determined. Key words: labour contracting parties, the regulation of labour relations, the interest, contractual regulation of labour relations

In Situ Pore Formation in Graphite Through Solvent Co-Intercalation: A New Model for The Formation of Ternary Graphite Intercalation Compounds Bridging Batteries and Supercapacitors

For Li‐ion and Na‐ion batteries, the intercalation behavior of graphite anodes is quite different. While Li‐ions intercalate, Na‐ions only co‐intercalate with solvent molecules from the electrolyte solution leading to ternary graphite intercalation compound (t‐GIC) formation along with an expansion of the graphite interlayer spacing to 1.2 nm. This large interlayer spacing represents a micropore with parallel slit geometry. Little is known about t‐GIC formation, but it is commonly believed that throughout the reaction the ion is accompanied by either a full or partial solvation shell. Here, it is elucidated for the first time, using two independent methods – mass measurements and electrochemical impedance spectroscopy – supplemented by operando microscopy, entropymetry and simulations, that the storage mechanism is far more complex. A new model for the electrochemical solvent co‐intercalation process is proposed: As soon as solvated ions enter, the graphite structure is flooded with free solvents, which are subsequently replaced by solvated ions. Close to full sodiation, few free solvents remain and structural rearrangement take place to reach the full storage capacity. Thus, t‐GICs represent a unique case of switchable microporous systems and hence appear as a bridge between ion storage in the bulk phase and in micropores, i.e., between batteries and supercapacitors.Peer Reviewe

Towards low-cost sodium-ion batteries: electrode behavior of graphite electrodes obtained from spheroidization waste fractions and their structure-property relations

Electrode materials for lithium-ion batteries (LIBs) typically show spherical particle shapes. For cathode materials, the spherical shape is obtained through the synthesis method. For graphite, the by far most popular anode material for LIBs, spherical particles are obtained through a spheroidization process. The yield of that process is quite low and limited to about 50%, leaving substantial amounts of by-products. Using such lower quality by-products would be quite attractive for developing low-cost energy stores like sodium-ion batteries (SIBs), for which the requirements for particle sizes and shapes might be less strict as compared to high performing LIBs. Here, we study three different graphite ‘waste fractions’ as anode material for SIBs that are obtained from the spheroidization process and how they compare to LIB battery grade material. Only negligible differences between the fractions are found when analyzing them with x-ray diffraction (XRD), Raman spectroscopy and elemental analysis (EA). More clear differences can be seen from N2 physisorption, scanning electron microscopy (SEM) and particle size analysis. For example, the surface areas of the ‘waste fractions’ can become roughly up to twice as large as compared to the battery grade fraction and the d 50 values shift by up to 11.9 µm to lower numbers. Electrochemical measurements show that the ‘waste fractions’ can deliver the full electrode capacity and behave similar to the battery grade fraction up to 10 C. However, the higher surface areas lead to more irreversible losses in the first cycle. A surprising finding is that all graphite fractions show almost identical discharge voltages, while the charging voltages differ by as much as 200 mV. This asymmetric behavior only occurs in SIBs and not in LIBs, which indicates a more complex storage behavior in case of sodium.H2020 European Research Councilhttp://dx.doi.org/10.13039/100010663Bundesministerium für Bildung und Forschunghttp://dx.doi.org/10.13039/501100002347Deutsche Forschungsgemeinschafthttp://dx.doi.org/10.13039/501100001659EIG Concert JapanPeer Reviewe

Electrochemical Properties of Layered NaxNix 2Mn1 x 2O2 0.5 amp; 8201; amp; 8804; amp; 8201;x amp; 8201; amp; 8804; amp; 8201;1.1 with P3 Structure as Cathode for Sodium Ion Batteries

The Na properties of Ni and Mn containing layered oxides of the type Na x Ni x 2Mn1 amp; 8722;x 2O2 are explored between Na contents of 0.5 amp; 8804;x amp; 8804;1.1. Charge balance is maintained by adjusting the Ni Mn ratio. X ray diffraction and scanning electron microscopy are used to characterize the structure and morphology. The primary phase for all as synthesized materials is P3, especially at Na contents below x amp; 8201; amp; 8804; amp; 8201;0.8. Samples with a Na content of x amp; 8201; amp; 8805; amp; 8201;0.9 lead to the formation of Na and Ni secondary phases. The Na storage properties are studied in half cells with two different voltage windows between 1.5 4.0 amp; 8201;V and 2.2 4.5 amp; 8201;V vs Na Na . Ni and Mn redox are active between 1.5 and 4.0 amp; 8201;V accompanying three voltage plateaus at 3.7, 3.0, and 2.1 amp; 8201;V, respectively. An additional high voltage plateau gt;4.0 amp; 8201;V is observed when increasing the cutoff voltage to 4.5 amp; 8201;V. The initial Na content has a strong influence on the discharge capacity which ranges from 90 amp; 8201;mAh amp; 8201;g amp; 8722;1 x amp; 8201; amp; 8201;1.1 to 210 amp; 8201;mAh amp; 8201;g amp; 8722;1 x amp; 8201; amp; 8201;0.6 . C rate tests up to 2C and cycle life over 150 cycles are discussed. Overall, the composition Na0.6Ni0.3Mn0.7O2 shows the most favorable properties with respect to capacity retention, rate capability, and initial Coulomb efficienc