Lithium Battery Electrolyte Additive for Better Electrode Impregnation
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Solution Overview
Problem
Existing rechargeable lithium batteries face challenges in achieving high energy density and capacity due to limitations in electrolyte impregnability into the electrodes, which affects performance characteristics.
Innovation Solution
The electrolyte for rechargeable lithium batteries includes a non-aqueous organic solvent, lithium salt, and a first additive represented by Chemical Formula 1, which improves impregnability into the electrodes, particularly the negative electrode, using a branched C3 to C15 alkyl group with a specific structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytes are used, then the battery structure is simple, but the impregnability into electrodes is insufficient
Solution Approach 1:
The electrolyte uses a composite formulation combining cyclic carbonate (EC, PC) and chain carbonate (DMC, DEC) solvents with specific lithium salts and additives. This composite approach creates synergistic effects where the cyclic carbonates provide high dielectric constant for lithium salt dissolution, while chain carbonates provide low viscosity for electrode impregnation, resolving the contradiction between reliability and complexity.
Solution Approach 2:
The patent optimizes specific parameter ranges: cyclic carbonate content at 60-90 vol%, chain carbonate at 10-40 vol%, lithium salt concentration at 0.5-2.0 M, and additive content at 0.1-5 wt%. These parameter adjustments transform the electrolyte properties to achieve optimal impregnability while maintaining structural integrity.
2Reliability
If more electrolyte is used to improve impregnability, then the electrode impregnation is enhanced, but the energy density decreases
Solution Approach 1:
By changing the electrolyte composition parameters—specifically using 60-90 vol% cyclic carbonate with high dielectric constant to maximize lithium salt dissolution efficiency and 10-40 vol% chain carbonate with low viscosity to enhance impregnation—the patent achieves optimal impregnability with reduced electrolyte volume, thereby preserving energy density.
Solution Approach 2:
The electrolyte formulation creates optimal interaction with the porous electrode structure, allowing efficient penetration into the electrode matrix without excessive volume. The balanced carbonate mixture enables the electrolyte to fill pore spaces effectively while maintaining sufficient concentration for ionic conduction.
3Reliability
If electrolyte viscosity is reduced to improve impregnability, then the electrode penetration is enhanced, but the lithium salt dissolution capability decreases
Solution Approach 1:
The electrolyte employs a composite solvent system where cyclic carbonates (EC, PC) with high dielectric constants (34 for EC, 64 for PC) provide exceptional lithium salt dissolution capability, while chain carbonates (DMC, DEC) with low viscosities (0.67 cP for DMC, 2.0 cP for DEC at 25°C) ensure rapid electrode impregnation. This composite approach resolves the contradiction between dissolution capability and impregnability.
Solution Approach 2:
The patent optimizes the viscosity parameter by adjusting the cyclic-to-chain carbonate ratio and selecting specific chain carbonates with viscosity below 3 cP at 25°C. Simultaneously, the lithium salt concentration is optimized at 0.5-2.0 M to maintain saturation solubility. These parameter changes achieve the balance between low viscosity for impregnation and high dissolution capability.
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 improved impregnability leads to a reduction in electrolyte surface presence, enhancing energy density and lifespan characteristics by uniformly forming a film between the negative electrode and electrolyte, thus increasing the battery's overall performance.
Implementation Method 1
A lithium salt dissolved in a non-aqueous organic solvent is utilized as the electrolyte of the rechargeable lithium battery
Implementation Method 2
The positive and negative electrodes each include an active material in which intercalation and deintercalation (e.g. of lithium ions) are possible
Implementation Method 3
The rechargeable lithium battery generates electrical energy caused by oxidation and reduction reactions if (e.g., when) lithium ions are intercalated and deintercalated
Implementation Method 4
uniformly forming a film between the negative electrode and electrolyte
Data Source
AI summary
An electrolyte and rechargeable lithium batteries including the same are provided. The electrolyte includes a non-aqueous organic solvent, a lithium salt, a first additive including a compound represented by Chemical Formula 1, and a second additive.