lithium-ion battery

DOI: https://doi.org/10.18500/1608-4039-2018-18-2-51-76

DOI: https://doi.org/10.18500/1608-4039-2017-17-4-235-248

DOI: https://doi.org/10.18500/1608-4039-2017-17-2-99-119

УДК 541.136

DOI:  https://doi.org/10.18500/1608-4039-2016-16-3-100-121

This work is dedicated to phosphoric acid esters working as solvents for lithium-ion and supercapacitor (SC) electrolyte. The electrical conductivity of electrolytes based on phosphoric acid esters, lithium salts, commonly used in lithium-ion batteries (LIB), and salts used in SC technology was measured. The thermodynamic stability of new electrolytes in comparison with other solvents used in chemical power sources technology was also estimated. It was shown that the thermodynamic stability of phosphoric acid ester increases in a homologous series.

It is shown that the performance of lithium-ion battery is significantly affected by the component structure of the electrodes, electrode fabrication technology, forming the battery mode. It is shown that in the production of lithium-ion batteries can be used the following materials: as a binder – polymer dispersion of water-based СНР 500, the negative electrode material – synthetic graphite 131181008–1 brands and 20130905.

The study of the internal resistance of the lithium-ion battery designed and manufactured by JSC «Saturn» as the original, and after a long cycle life by pulse chronopotentiometry and electrochemical impedance was carried out. It is shown that the higher the hexagonal ordering of the material and the closer the degree of cation mixing to the optimal value, the less polarization resistance of the battery as original, and after a long cycle life. It was found that the less the original polarization resistance of the battery, the more its cyclic life.

Structure of thin-film electrodes manufactured by layer-by-layer magnetron sputtering of Si and Al in the environment with small oxygen additives has been studied. Charge-discharge behavior of these electrodes was studied as well. It is shown that such electrodes are able to stable cycling with marginal irreversible capacity.

A series of solid phases (mixed lithium-iron-manganese phosphates) of the common formula LiMn_yFe_1-yPO₄ (0 ≤ y ≤ 1) with a carbon coating on the particle surface was synthesized by mechanochemical activation with carbothermal reduction. The synthesized mixed phosphates were examined as promising cathode materials for lithium-ion batteries. The positive effect of replacement of a rather small fraction of iron by manganese is shown, which improves the electrochemical performance at the rates C/10–10C. The highest discharging capacity (above 160 mA·h/g at the C/10 rate, about 100 mA·h/g at the 10C rate) and cycling stability (the capacity decrease rate less than 0.05 mA·h/g per cycle at the 10 C rate) were established for the weakly doped cathode material LiMn_0.05Fe_0.95PO₄.

It is shown that the nonlinear structural model of the battery can be used for modeling the voltage relaxation processes after a charge of batteries. The solution obtained is valid for alkaline, acid and lithium-ion batteries. Comparison of solutions, with the experimental data for nickel-cadmium batteries, showed, that the relative error does not exceed 3%.