Lithium Battery Electrolyte Additive for Ni-Rich Cathode Interface Stability

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Solution Overview

Problem

Conventional lithium secondary batteries using lamella nickel (Ni)-rich LiNi1-x-yCoxMnyO2 oxide as a high-capacity positive electrode material face rapid degradation due to residual lithium components promoting electrolyte degradation and interfacial reactivity, necessitating improved electrolyte additives to form stable films and control interfaces.

Innovation Solution

Incorporation of a functional additive, 5,5-diallyl-3-(tert-butyldimethylsilyl)oxazolidin-2-one, in the electrolyte to form a protective film on the positive electrode, along with vinylene carbonate for the negative electrode, to stabilize the electrode-electrolyte interface and scavenge harmful components like hydrogen fluoride.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the content of Ni is increased or charge voltage is raised to increase positive electrode capacity, then energy density is improved, but charge/discharge performance degrades rapidly due to electrolyte degradation and interfacial reactivity

Engineering Contradiction:

Improvepositive electrode capacityVSAvoidcharge/discharge performance stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent introduces a film-forming additive as an intermediary substance between the high-Ni positive electrode and the electrolyte. This additive forms a protective interface film that mediates the interaction between the electrode and electrolyte, preventing direct harmful reactions while allowing lithium ion transport, thus resolving the contradiction between high capacity and performance stability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful residual lithium components (Li2CO3 and LiOH) on the positive electrode surface into beneficial elements by using film-forming additives that preferentially react with these components to form stable protective films. This transforms the harmful interfacial reactivity into a controlled film formation process that protects against further degradation

Inventive Principle:

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

2Quantity of substance

If residual lithium components (Li2CO3 and LiOH) are present on the positive electrode, then high capacity is achieved, but electrolyte degradation is promoted and interfacial reactivity increases

Engineering Contradiction:

Improvepositive electrode capacityVSAvoidelectrolyte degradation and interfacial reactivity

Core Design Contradiction:

Quantity of substanceVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful residual lithium components into beneficial elements by using film-forming additives that preferentially react with these components to form stable protective films, transforming the harmful interfacial reactivity into a controlled film formation process

Inventive Principle:

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

Solution Approach 2:

The film-forming additive acts as a sacrificial component that is consumed during initial cycles to form the protective film. This disposable additive sacrificially reacts with harmful residual lithium components, protecting the main electrolyte and electrode from degradation

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 proposed electrolyte additives enhance the lifetime and output characteristics of lithium secondary batteries by forming stable films that prevent degradation, improve initial cell efficiency, and maintain performance at high temperatures.

Implementation Method 1

introduction of an additive technique capable of forming an electrochemically and chemically stabile film is required

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Implementation Method 2

forming an electrochemically and chemically stabile film

Methodology Applied

Scientific EffectSurface passivation: Adsorption

Implementation Method 3

The functional additive may further include vinylene carbonate (VC) as a negative electrode film additive

Methodology Applied

Scientific EffectFilm formation: Deposition (physical)

Implementation Method 4

scavenge harmful components like hydrogen fluoride

Methodology Applied

Scientific EffectScavenging: Absorption (physical)

Implementation Method 5

stabilize the electrode-electrolyte interface

Methodology Applied

Scientific EffectInterface stabilization: Adsorption

Data Source

PatentUS12438193B2Electrolyte solution for a lithium secondary battery and a lithium secondary battery including same

Publication Date: 2025.10.07 HYUNDAI MOTOR CO LTD

AI summary

Disclosed herein are an electrolyte for a lithium secondary battery, which can enhance lifetime and output characteristics in a high-capacity lithium secondary battery, and a lithium secondary battery including the same. The electrolyte for a lithium secondary battery may include a lithium salt, a solvent, and a functional additive, wherein the functional additive includes 5,5-diallyl-3-(tert-butyldimethylsilyl)oxazolidin-2-one as a positive electrode film additive.