Lithium Secondary Battery Electrolyte With Acrylate Interface Protection
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Solution Overview
Problem
Lithium secondary batteries face challenges in maintaining low-temperature resistance and capacity retention during high-temperature storage and charge/discharge cycles, with issues of electrochemical decomposition at the electrode interface and reduced capacity due to high temperature exposure.
Innovation Solution
A lithium secondary battery design incorporating a positive electrode with a highly loaded positive electrode material mixture layer and a non-aqueous electrolyte solution containing a high concentration lithium salt and a specific acrylate-based additive, which improves lithium ion mobility and reduces solvent decomposition, enhancing storage and cycle life characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high concentration lithium salt is used in the non-aqueous electrolyte solution, then low-temperature resistance characteristics are improved, but manufacturing complexity increases due to precise concentration control requirements
Solution Approach 1:
The patent applies parameter changes by optimizing the lithium salt concentration to a specific high concentration range (2.0-2.5 M) and controlling the additive concentration within 0.1-3.0 wt%. These precise parameter specifications resolve the contradiction by establishing clear manufacturing targets that improve low-temperature resistance while providing actionable guidelines for production control.
2Quantity of substance
If the positive electrode material mixture layer is highly loaded, then capacity characteristics are improved, but electrochemical decomposition at the electrode interface increases
Solution Approach 1:
The patent introduces an intermediary substance - the acrylate-based additive (Formula 1) - that mediates between the highly loaded positive electrode material and the electrolyte. This additive forms a protective interface layer that prevents electrochemical decomposition while allowing the high capacity characteristics to be achieved through increased loading (3.5-4.0 mAh/cm²).
Solution Approach 2:
The patent converts the potentially harmful effect of high loading (which causes interface stress and decomposition) into a benefit by using the acrylate additive to create a stable solid electrolyte interface. The high loading that would normally cause decomposition is instead harnessed to achieve high capacity (82% retention after 150 cycles at 45°C) when protected by the additive-formed interface layer.
3Duration of action of stationary object
If storage time at high temperature is extended, then capacity retention decreases, but thermal decomposition reactions accelerate
Solution Approach 1:
The patent applies preliminary action by having the acrylate-based additive react first during initial charging cycles to form a stable protective film on the electrode surface. This pre-formed protective layer prevents subsequent thermal decomposition reactions during extended high-temperature storage, enabling 82% capacity retention after 6 weeks at 60°C by blocking decomposition pathways before they can occur.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The battery achieves improved capacity retention and stability at both low and high temperatures, with capacity retention of 82% or more after 6 weeks at 60°C and 150 cycles at 45°C, while maintaining low internal resistance and preventing side reactions.
Implementation Method 1
a non-aqueous electrolyte solution including a lithium salt, an organic solvent, and a compound represented by Formula (1) as a first additive
Implementation Method 2
a compound represented by Formula (1) as a first additive, wherein R1 is an alkylene group having 1 to 5 carbon atoms which is unsubstituted or substituted with fluorine, or -R1'-O-
Data Source
Figure 1
AI summary
The present invention relates to a lithium secondary battery having improved high-temperature characteristics, and particularly to a lithium secondary battery which includes a positive electrode including a positive electrode material mixture layer formed on a positive electrode collector, a negative electrode including a negative electrode material mixture layer formed on a negative electrode collector, a separator disposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte solution including a lithium salt, an organic solvent, and a compound represented by Formula 1 as a first additive, wherein the positive electrode material mixture layer has a loading capacity of 3.7 mAh/cm2 to 10 mAh/cm2, the concentration of the lithium salt in the non-aqueous electrolyte solution is 1.5 M to 3 M, the organic solvent is a mixed solvent including a cyclic carbonate-based organic solvent and a linear carbonate-based organic solvent, and the compound represented by Formula 1 is included in an amount of 0.1 wt% to 5 wt% based on a total weight of the non-aqueous electrolyte solution.