Silicon-Composite Lithium Battery Electrolyte for Stable SEI Layers

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Solution Overview

Problem

Lithium batteries face challenges in maintaining high-temperature stability and lifespan due to the degradation of the solid electrolyte interface (SEI) layer and protection layer, leading to reduced discharge capacity and reversibility of lithium ion intercalation/deintercalation.

Innovation Solution

Incorporating a bicyclic sulfate-based compound in the organic electrolytic solution, which forms a durable modified SEI layer and protection layer on the anode and cathode surfaces, enhancing thermal stability and lifespan characteristics by blocking direct contact between the organic solvent and electrodes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional organic electrolytic solution is used, then the battery can operate, but the SEI layer and protection layer degrade at high temperatures leading to reduced discharge capacity and reversibility

Engineering Contradiction:

Improvehigh-temperature stabilityVSAvoidlifespan

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The bicyclic sulfate-based compound acts as an intermediary substance that mediates between the organic electrolytic solution and the electrode surfaces. It forms a modified SEI layer and protection layer that prevent direct contact between the organic solvent and electrodes, thereby improving high-temperature stability and lifespan while maintaining electrochemical performance.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical composition parameters of the electrolytic solution by introducing a bicyclic sulfate-based compound with specific molecular structure (Formula 1) containing sulfate ester groups. This parameter change transforms the properties of the SEI layer and protection layer, making them more stable at high temperatures and resistant to degradation.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If silicon content is increased in the anode active material layer, then discharge capacity is improved, but structural stability may be compromised

Engineering Contradiction:

Improvedischarge capacityVSAvoidstructural stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The invention applies local quality by creating a non-uniform distribution of silicon content across different layers of the anode active material. The first layer has higher silicon content for enhanced discharge capacity, while the second layer has lower silicon content to provide structural stability and accommodate volume expansion, thus resolving the contradiction between capacity and stability.

Inventive Principle:

Principle #3Local quality

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 modified layers improve the battery's high-temperature stability and lifespan by increasing discharge capacity and reversibility of lithium ion intercalation/deintercalation, resulting in enhanced performance.

Implementation Method 1

the degradation of the solid electrolyte interface (SEI) layer and protection layer, leading to reduced discharge capacity and reversibility of lithium ion intercalation/deintercalation

Methodology Applied

Scientific EffectSolid electrolyte interface (SEI) layer formation:

Implementation Method 2

forms a durable modified SEI layer and protection layer on the anode and cathode surfaces, enhancing thermal stability and lifespan characteristics by blocking direct contact between the organic solvent and electrodes

Methodology Applied

Scientific EffectPhysical barrier formation:

Implementation Method 3

reversibility of lithium ion intercalation/deintercalation

Methodology Applied

Scientific EffectIntercalation:

Data Source

PatentUS12573611B2Lithium battery

Publication Date: 2026.03.10 SAMSUNG SDI CO LTD

AI summary

A lithium battery includes a cathode; an anode; and an organic electrolytic solution between the cathode and the anode, wherein the anode includes an anode current collector and an anode active material layer on the anode current collector, the anode active material layer includes carbonaceous and silicon-containing composite anode active materials, the anode active material layer includes first and second anode active material layers, and the first anode active material layer is between the anode current collector and the second anode active material layer, a content of silicon in the first anode active material layer is higher than the second anode active material layer, and the organic electrolytic solution includes a first lithium salt, an organic solvent, and a bicyclic sulfate-based compound represented by Formula 1 below: