Lithium-Rich Negative Electrode Plate with Cyclic Ester SEI Film

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Solution Overview

Problem

Lithium-ion batteries face challenges in maintaining security, stability, and extending service life after lithium supplementation, as existing methods compromise their performance.

Innovation Solution

A lithium-rich negative electrode plate is developed, incorporating a cyclic ester with a dielectric constant of 10 or higher and a reduction potential ≤1.5V, which forms a protective SEI film, controlling lithium intercalation speed and ensuring uniformity, while enhancing the bond strength between the electrode film and collector.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If lithium supplementation technology is applied to extend service life, then cycle life is improved, but security and stability deteriorate

Engineering Contradiction:

Improveservice lifeVSAvoidsecurity and stability

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

A cyclic ester additive is introduced as an intermediary substance in the electrolyte that mediates between the lithium supplementation need and security requirements. The cyclic ester forms a protective SEI film that acts as an intermediary layer, controlling lithium intercalation speed and preventing direct harmful interactions between lithium and electrode materials, thus extending service life while maintaining security and stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If lithium intercalation speed is increased to improve productivity, then charge rate is improved, but uniformity of lithium distribution deteriorates

Engineering Contradiction:

Improvecharge rateVSAvoiduniformity of lithium distribution

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The cyclic ester additive changes the electrochemical parameters of the electrolyte system, specifically modifying the SEI film formation characteristics. By adjusting the composition and properties of the SEI film through cyclic ester, the lithium intercalation speed is controlled and uniformity of lithium distribution is maintained even at high charge rates, resolving the contradiction between productivity and uniformity.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If conventional electrode materials are used to maintain simplicity, then device complexity is low, but bond strength between electrode film and collector deteriorates

Engineering Contradiction:

Improveelectrode structure simplicityVSAvoidbond strength between electrode film and collector

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The cyclic ester additive changes the interfacial properties and bonding characteristics between the electrode film and collector by modifying the SEI film composition. This parameter change in the interface properties enhances adhesion strength without requiring complex structural modifications, maintaining device simplicity while improving bond strength.

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 solution effectively improves the film formation effect, security, and stability of lithium-ion batteries, leading to longer cycle and storage life by maintaining the cyclic ester's participation in the SEI film's dissolving-repairing process.

Implementation Method 1

the negative electrode film further comprises a cyclic ester which is capable of forming a film on the negative electrode plate

Methodology Applied

Scientific EffectSEI film formation: Electrochemiluminescence

Implementation Method 2

a reduction potential of the cyclic ester relative to Li/Li+ is lower than or equal to 1.5V

Methodology Applied

Scientific EffectElectrochemical reduction: Reduction

Implementation Method 3

a dielectric constant of the cyclic ester is larger than or equal to 10

Methodology Applied

Scientific EffectDielectric effect: Dielectric

Implementation Method 4

control the lithium intercalation speed of the negative electrode plate, ensure the lithium intercalation uniformity

Methodology Applied

Scientific EffectIntercalation: Absorption (physical)

Implementation Method 5

a lithium-ion battery which comprises a negative electrode plate, a positive electrode plate, a separator and an electrolyte

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentUS11482705B2Lithium-rich negative electrode plate, electrode assembly and lithium-ion battery

Publication Date: 2022.10.25 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

AI summary

The present disclosure provides a lithium-rich negative electrode plate, an electrode assembly and a lithium-ion battery, the lithium-rich negative electrode plate comprises a negative electrode collector and a negative electrode film, the negative electrode film is provided on a surface of the negative electrode collector and comprises a negative electrode active material, the lithium-rich negative electrode plate further comprises a layer of lithium metal provided on a surface of the negative electrode film. The negative electrode film further comprises a cyclic ester which is capable of forming a film on the negative electrode plate, a dielectric constant of the cyclic ester is larger than or equal to 10, and a reduction potential of the cyclic ester relative to Li/Li+ is lower than or equal to 1.5V.