Литиевые и постлитиевые электрохимические системы

The increasing of cathode characteristics of nanodispersed materials on the base of nanodispersed titania modified by α-Fe and Fe3O4 injection and also laser irradiation has been studied and models of Fe-containing particles injection was optimized. The globule structure of modified cathode materials was established as a result of complex experimental investigations (X-ray diffractometry, Mössbauer spectroscopy, optical microscopy).

The correlation between the Coulombic efficiency and the change in the residual capacity of electrodes and batteries under conditions without any parallel irreversible reactions was formulated. It was shown that this relationship allows drawing certain conclusions regarding the nature of degradation processes during cycling.

In the last decade, the use of lithium-ion batteries in transport, power engineering and industry has expanded. Batteries operate under the control of electronic battery management systems (BMS), one of the functions of which is balancing the cells in the battery. The article presents a method for imitational statistical modeling of charge-discharge cycles of lithium-ion batteries.

In this paper, we compare electrode composites based on Li3V2(PO4)3 and carbon according to their initial characteristics in the galvanostatic cycling mode and structural features. The composites were synthesized using carbon black or starch as carbon sources. The electrode material obtained using starch demonstrates a higher specific capacity, the stability of which is lower during cycling, while characterized by a smaller unit cell volume and a larger crystallite size.

The influence of the structural parameters of lithium battery cathodes on their characteristics has been studied. To explain the results obtained, a macrokinetic model of the electrode was applied, and mathematical simulation of the electrode discharge process was conducted. The nested ball model was used to describe the electrode structure. The data obtained during simulation are in good agreement with the practical results of electrode testing, which confirms the need for targeted optimization of the particle sizes in the cathode.

It is shown that the composition and the quality of the binder for the electrodes of lithium iron phosphate battery significantly affect its performance and cycle life. The data presented confirm that the LA132-type aqueous binder compositions can be used in the production of lithium iron phosphate batteries. It has been established that the use of nanotubes and an aqueous binder in the production of graphite anodes and lithium iron phosphate cathodes improves stability, service life, and specific performance of lithium-ion batteries.

The analysis of electrochemical impedance of lithium-sulfur cells is complicated by the complexity of the processes occurring inside them. Both electrochemical processes and mass transport processes simultaneously occur on the lithium and sulfur electrodes of the cells, as well as in the bulk electrolyte. A comparative analysis of the distribution functions of relaxation times of symmetric Li||Li, S||Sand and the full lithium-sulfur cell has been conducted.

When cycling anode-free sodium batteries, unbalanced volumetric changes in opposite electrodes arise. This problem leads to volumetric changes in the whole battery. While charging the negative electrode, the volume increase corresponds to 0.88 cm3 /A·h. The current study evaluates the volume decrease while charging the positive electrodes which are based on sodium vanadophosphate, sodium fluorovanadophosphate, sodium hexacyanoferrate, and sodiated iron sulfide Na1.5FeS2.