Lithium Battery Electrolyte Additives for Stable SEI at High Temperature

Solution Overview

Problem

Existing lithium batteries face challenges in achieving high-temperature stability, lifespan, and voltage performance due to limitations in the electrolyte composition.

Innovation Solution

Incorporation of a bicyclic sulfate-based compound and a nitrile group-containing compound in the organic electrolytic solution, along with specific lithium salts and cyclic carbonate compounds, to form a stable solid electrolyte interface (SEI) layer and protection layer on the anode and cathode surfaces, enhancing thermal stability and lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrolyte composition is used, then basic battery function is maintained, but high-temperature stability and lifespan are insufficient

Engineering Contradiction:

Improvehigh-temperature stabilityVSAvoidlifespan

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent modifies the electrolyte composition by introducing specific compounds (bicyclic sulfate-based compound with formula 1 and nitrile group-containing compound with formula 2) and controlling their concentrations within specific ranges (0.1-5 wt% and 0.01-1 wt% respectively). This parameter change in chemical composition enables the formation of stable SEI and protection layers, thereby improving high-temperature stability and lifespan simultaneously

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite electrolyte system by combining multiple components: cyclic carbonate compound (10-40 vol%), chain carbonate compound (50-85 vol%), bicyclic sulfate-based compound (0.1-5 wt%), and nitrile group-containing compound (0.01-1 wt%). This composite approach allows the different components to work synergistically, where the cyclic and chain carbonates provide basic electrolyte function while the specialized compounds form protective layers, resolving the contradiction between reliability and lifespan

Inventive Principle:

Principle #40Composite materials

2Productivity

If electrolyte composition is modified to improve performance, then discharge capacity and high-temperature performance improve, but electrolyte composition complexity increases

Engineering Contradiction:

Improvedischarge capacityVSAvoidelectrolyte composition complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent optimizes the concentration parameters of each electrolyte component to achieve high discharge capacity while maintaining manageable complexity. Specifically, the bicyclic sulfate-based compound is controlled at 0.1-5 wt% and the nitrile group-containing compound at 0.01-1 wt%, which are sufficient to form effective protective layers without excessive complexity in the overall composition

Inventive Principle:

Principle #35Parameter changes

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 SEI and protection layers improve the battery's discharge capacity, lifespan, and high-temperature performance by blocking solvent co-intercalation and suppressing side reactions, resulting in enhanced battery characteristics.

Implementation Method 1

Incorporation of a bicyclic sulfate-based compound and a nitrile group-containing compound in the organic electrolytic solution, along with specific lithium salts and cyclic carbonate compounds, to form a stable solid electrolyte interface (SEI) layer and protection layer on the anode and cathode surfaces

Methodology Applied

Scientific EffectSolid electrolyte interface (SEI) layer formation:

Implementation Method 2

Incorporation of a bicyclic sulfate-based compound and a nitrile group-containing compound in the organic electrolytic solution, along with specific lithium salts and cyclic carbonate compounds, to form a stable solid electrolyte interface (SEI) layer and protection layer on the anode and cathode surfaces

Methodology Applied

Scientific EffectProtection layer formation:

Implementation Method 3

The modified SEI and protection layers improve the battery's discharge capacity, lifespan, and high-temperature performance by blocking solvent co-intercalation and suppressing side reactions

Methodology Applied

Scientific EffectBlocking solvent co-intercalation:

Data Source

PatentUS12597640B2Organic electrolytic solution and lithium battery including the same

Publication Date: 2026.04.07 SAMSUNG SDI CO LTD

AI summary

An organic electrolytic solution includes a first lithium salt; an organic solvent; a bicyclic sulfate-based compound represented by Formula 1 below; and a nitrile group-containing compound, wherein the nitrile group-containing compound includes a plurality of nitrile groups:in Formula 1, each of A1, A2, A3, and A4 is independently a covalent bond, a substituted or unsubstituted C1-C5 alkylene group, a carbonyl group, or a sulfinyl group, wherein both A1 and A2 are not a covalent bond and both A3 and A4 are not a covalent bond.