Lithium Battery Electrolyte Additive for Stable High-Ni Cathodes

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Solution Overview

Problem

Lithium secondary batteries with high energy density cathode active materials face stability issues due to side reactions between the cathode and electrolyte, leading to capacity and lifetime deterioration.

Innovation Solution

Incorporating an unsaturated compound in the electrolyte, specifically a sulfonate compound with double or triple bonds, which forms a stable solid electrolyte interphase (SEI) film on the anode, reducing side reactions and improving electrochemical stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a cathode active material with increased discharge capacity is used to achieve high energy density, then the energy density is improved, but the electrochemical stability deteriorates due to side reactions with the electrolyte

Engineering Contradiction:

Improveenergy densityVSAvoidelectrochemical stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces a mediator substance (coating material such as aluminum oxide, aluminum hydroxide, or boehmite) that forms a protective intermediate layer between the cathode active material and the electrolyte. This coating layer prevents direct contact and side reactions between the high-capacity cathode material and the electrolyte, thereby maintaining electrochemical stability while preserving the high energy density benefits.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the surface properties of the cathode active material by applying a coating layer, which changes the physical and chemical parameters of the cathode-electrolyte interface. This parameter change (surface coating) reduces the reactivity between the cathode material and electrolyte, improving electrochemical stability without compromising the bulk energy density characteristics.

Inventive Principle:

Principle #35Parameter changes

2Power

If a cathode active material with increased discharge capacity is used, then the discharge capacity is improved, but side reactions with the electrolyte occur leading to stability deterioration

Engineering Contradiction:

Improvedischarge capacityVSAvoidside reactions

Core Design Contradiction:

PowerVSObject-generated harmful factors

Solution Approach 1:

A coating layer consisting of aluminum oxide, aluminum hydroxide, or boehmite is applied to the cathode active material surface. This intermediary layer acts as a physical barrier that prevents harmful side reactions between the high-capacity cathode material and the electrolyte, while allowing ionic transport to maintain discharge capacity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the potentially harmful high reactivity of high-capacity cathode materials into a benefit by using the coating layer to control and direct the reactions. The coating material itself undergoes controlled reactions to form a stable surface layer that protects the underlying high-capacity material, transforming the stability issue into a protective mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 unsaturated compound minimizes side reactions, reduces gas generation, and enhances the lifetime and performance of lithium batteries by maintaining affinity with Ni cations and forming a protective SEI film, even under high voltage conditions.

Implementation Method 1

Incorporating an unsaturated compound in the electrolyte, specifically a sulfonate compound with double or triple bonds, which forms a stable solid electrolyte interphase (SEI) film on the anode

Methodology Applied

Scientific EffectSolid electrolyte interphase (SEI) film formation:

Implementation Method 2

The unsaturated compound minimizes side reactions, reduces gas generation, and enhances the lifetime and performance of lithium batteries by maintaining affinity with Ni cations

Methodology Applied

Scientific EffectSide reaction suppression through cation affinity:

Data Source

PatentEP3696901B1Lithium secondary battery

Publication Date: 2025.03.26 SAMSUNG SDI CO LTD

AI summary

Provided herein is a lithium battery including: a cathode; an anode; and an electrolyte between the cathode and the anode, wherein the cathode includes a cathode active material represented by Formula 1, and the electrolyte includes a lithium salt, a non-aqueous solvent, and an unsaturated compound represented by Formula 2: <Formula 1> LixNiyM1-yO2-zAz wherein definitions of x, y, z, M, A, Q1, and Q2 in Formulae 1 and 2 are the same as those described in the detailed description of the present specification.