Non-Aqueous Electrolyte Composition for Stable Battery SEI Layers
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Solution Overview
Problem
Lithium secondary batteries face challenges in maintaining high-temperature stability and life characteristics due to electrolyte decomposition reactions at the electrode-electrolyte interface, particularly when exposed to high temperatures, leading to increased resistance and degradation.
Innovation Solution
A non-aqueous electrolyte solution comprising specific silane-based compounds and other additives forms a stable, low-resistance solid electrolyte interface (SEI) layer, enhancing the battery's high-temperature stability and life characteristics by forming a robust SEI layer through covalent bonds and crosslinking agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte solutions are used in lithium secondary batteries, then the battery can achieve high capacity and output, but the electrolyte decomposes at high temperatures leading to increased resistance and degraded life characteristics
Solution Approach 1:
The silane-based compound performs preliminary action by forming a protective SEI layer on the electrode surface before high-temperature degradation can occur. This pre-formed interface layer prevents subsequent electrolyte decomposition and maintains stable battery performance during high-temperature operation and long-term storage.
Solution Approach 2:
The silane-based compound acts as an intermediary substance between the electrolyte and the electrode. It forms an intermediate SEI layer that mediates the interaction, preventing direct contact and harmful reactions between the electrolyte and electrode at high temperatures, thereby improving both reliability and life characteristics.
2Quantity of substance
If high-capacity positive electrode active materials are used to increase energy density, then the battery capacity increases, but the materials have low stability and require protective interface formation
Solution Approach 1:
The silane-based compound serves as an intermediary protective layer between the high-capacity but unstable positive electrode active material and the electrolyte. This intermediate SEI layer stabilizes the material composition by preventing direct electrolyte contact and degradation reactions, enabling the use of high-capacity materials without sacrificing stability.
Solution Approach 2:
The invention creates a composite interface structure consisting of the silane-based compound integrated into the SEI layer on the positive electrode. This composite material approach combines the high capacity characteristics of the active material with the protective and stabilizing properties of the silane-derived interface layer.
3Reliability
If the SEI layer is formed to protect the electrode, then high-temperature stability improves, but the SEI layer may collapse during high-temperature storage causing electrode exposure and side reactions
Solution Approach 1:
The silane-based compound performs preliminary protective action by forming a robust, crosslinked SEI layer that is specifically designed to maintain its structural integrity at high temperatures. This pre-formed stable interface prevents the collapse and electrode exposure problems that occur with conventional SEI layers during high-temperature storage.
Solution Approach 2:
The silane-based compound creates a composite SEI layer with enhanced structural properties. The crosslinked network structure of the silane-derived polymer provides mechanical strength and thermal stability, creating a composite protective layer that resists collapse and maintains its protective function even under high-temperature storage conditions.
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 results in a lithium secondary battery with improved high-temperature stability and extended life characteristics by reducing volume changes and internal resistance, thereby maintaining capacity and performance under harsh conditions.
Implementation Method 1
forming a robust SEI layer through covalent bonds and crosslinking agents
Implementation Method 2
forming a robust SEI layer through covalent bonds and crosslinking agents
Implementation Method 3
lithium ions from the lithium-containing transition metal oxide used as the positive electrode during the charge move to the carbon negative electrode active material used as the negative electrode and are intercalated thereinto
Implementation Method 4
the highly reactive lithium ions react with an electrolyte to form a compound, such as Li2CO3, Li2O, and LiOH, and these compounds form a solid electrolyte interface (SEI) layer on a surface of the electrode
Data Source
AI summary
Provided is a non-aqueous electrolyte solution that may improve high-temperature stability and life characteristics of a lithium secondary battery by forming a thin and stable SEI layer, wherein it comprises an organic solvent; a lithium salt; a compound represented by Formula I; and at least one selected from the compounds represented by Formula II to Formula Vwherein all the variables are as described herein.