Battery Electrolyte Additives for Low-Resistance Stable SEI Films
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Solution Overview
Problem
Conventional electrolyte solutions for lithium secondary batteries face challenges in improving output characteristics, especially at low temperatures, and suffer from gas generation and thickness increase issues due to poor additive properties, leading to degraded cycle characteristics and storage stability.
Innovation Solution
An electrolyte solution comprising an organic solvent, a lithium salt, a first additive with a vinyl terminal group, and a second additive with specific atomic structures, which reduces discharge resistance, enhances high-temperature recovery capacity, and suppresses gas generation and thickness increase, thereby forming a stable film on electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional electrolyte solution additives are used, then output characteristics may be improved, but gas generation and thickness increase occur leading to degraded cycle characteristics and storage stability
Solution Approach 1:
The patent changes the chemical structure parameters of the electrolyte solution additives by introducing specific functional groups (vinyl terminal groups with electronegativity ≥3 atoms) and controlling atomic composition (3-5 atoms total, 2-4 highly electronegative atoms). This structural parameter modification enables the additive to form stable films that improve output characteristics while preventing gas generation and thickness increase, thus resolving the contradiction between power and reliability.
Solution Approach 2:
The patent creates a composite functional structure by combining multiple elements (carbon, oxygen, and at least one highly electronegative atom with electronegativity ≥3) in a specific atomic ratio within the additive molecule. This composite atomic structure forms a stable protective film on the electrode surface that simultaneously enhances power output and maintains long-term cycle stability without gas generation issues.
2Power
If electrolyte solution additive amount is increased to improve output characteristics, then low-temperature output may be improved, but cathode surface decomposition and electrolyte oxidation occur during high temperature reaction
Solution Approach 1:
The patent optimizes the concentration parameter of the electrolyte solution additive to 0.01-10% by weight, which is sufficient to form a protective film at low temperatures for improved output characteristics. Simultaneously, the specific molecular structure (with vinyl terminal groups and highly electronegative atoms) ensures that even at this low concentration, the additive effectively prevents cathode surface decomposition and electrolyte oxidation during high-temperature reactions, resolving the contradiction between low-temperature power and high-temperature stability.
3Device complexity
If no electrolyte solution additive is used, then device complexity is reduced, but non-uniform SEI film formation occurs degrading low-temperature output characteristics
Solution Approach 1:
The patent introduces a simple yet effective molecular structure parameter change by using a small molecule additive (3-5 atoms total) with specific functional groups (vinyl terminal and highly electronegative atoms). This minimal structural addition to the electrolyte solution creates a uniform SEI film that dramatically improves low-temperature output characteristics while adding only 0.01-10% weight concentration, thus achieving significant performance improvement with minimal increase in system complexity.
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 solution improves battery output, extends lifespan, and maintains high-temperature storage stability by reducing internal resistance and gas generation, ensuring excellent performance and reliability for lithium secondary batteries.
Implementation Method 1
forming a stable film on electrodes
Implementation Method 2
oxidation-reduction reaction according to intercalation and desorption at the cathode and the anode
Implementation Method 3
an electrolyte solution between a cathode and an anode enables smooth movement of lithium ions
Implementation Method 4
significantly reducing gas generation and a thickness increase rate
Data Source
AI summary
The present invention relates to an electrolyte solution and a secondary battery including the same. According to the present invention, the present invention has an effect of providing a secondary battery having improved charging efficiency and output due to low discharge resistance and having a long lifespan and excellent high-temperature capacity retention by suppressing gas generation and increase in thickness.