Electrode for lithium ion secondary batteries, and lithium ion secondary battery

Abstract

The present invention provides: an electrode for lithium ion secondary batteries, which enables the achievement of a battery that is suppressed in decrease in the output power due to repeated charges and discharges even in cases where the volumetric energy density is high and an electrode holds only a small amount of an electrolyte solution; and a lithium ion secondary battery which uses this positive electrode. According to the present invention, a high dielectric solid oxide and a high concentration electrolyte solution are coexistent among active material particles within an electrode. Specifically, an electrode for lithium ion secondary batteries according to the present invention, which contains an electrode active material, a high dielectric solid oxide and an electrolyte solution, is configured such that: the high dielectric solid oxide and the electrolyte solution are arranged in the spaces that are formed among particles of the electrode active material; and the concentration of a lithium salt in the electrolyte solution is set to a value within the range of 0.5-3.0 mol / L.

Description

technical field [0001] The invention relates to an electrode for a lithium ion secondary battery and a lithium ion secondary battery using the electrode. Background technique [0002] Currently, lithium ion secondary batteries are widely used as secondary batteries having high energy density. A lithium ion secondary battery using a liquid as an electrolyte has a structure in which a separator is present between a positive electrode and a negative electrode and filled with a liquid electrolyte (electrolyte). [0003] Since the electrolytic solution of a lithium ion secondary battery is usually a flammable organic solvent, its thermal safety is particularly problematic. Therefore, a solid battery using a flame-retardant solid electrolyte instead of an organic liquid electrolyte has also been proposed. [0004] Such lithium ion secondary batteries have various requirements depending on applications. For example, when the application is a car, etc., it is desirable to have a ...

AI Technical Summary

Problems solved by technology

However, if the filling density of the electrode active material is increased, the gap between the active material particles inside the electrode will be reduced, and the amount of electrolyte held by the electrode will be relatively reduced.

[0010] Furthermore, in an electrode with a high filling density of the electrode active material, the electrode surface pressure increases due to the expansion of the negative electrode active material during charge and discharge, and the electrolyte solution present between the electrode active materials is squeezed out, making it easier to Electrolyte dry-out tendency occurs

[0011] Moreover, if charge and discharge are repeated in a state where the amount of electrolyte held by the electrode is insufficient or unevenly distributed, the resistance increases due to the lack of lithium ions, and a potential deviation occurs. As a result, the solvent constituting the electrolyte is easily decomposed. , it is easy to form a non-conductive film on the electrode

[0012] In the above case, even when the amount of electrolyte solution held by the electrodes is small, it is not fully realized for lithium-ion secondary batteries in which the decrease in output due to repeated charging and discharging is small. situation

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