Lithium-Ion Battery SEI Control for Fast Charging and Cycle Life

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Solution Overview

Problem

Lithium-ion secondary batteries face a challenge in improving charging capability while maintaining cycling stability, as enhancing rate performance often compromises their cycle life.

Innovation Solution

A lithium-ion secondary battery design incorporating specific additives and controlled particle sizes for the negative electrode active material forms a moderately thick and uniform SEI protective layer, enhancing interfacial stability and reducing uneven lithium intercalation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the rate performance is improved, then the charging capability is enhanced, but the cycling stability decreases

Engineering Contradiction:

Improvecharging capabilityVSAvoidcycling stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the electrolyte by introducing a specific fluorinated cyclic carbonate additive (Formula I) with controlled mass percentage (0.01-5%), which modifies the interfacial properties to enable both high rate performance and cycling stability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite protective interface layer on the negative electrode surface through the fluorinated additive, forming a composite structure that combines the benefits of fast lithium ion transport with enhanced structural stability during cycling

Inventive Principle:

Principle #40Composite materials

2Reliability

If a protective layer is formed on the negative electrode surface, then the cycling stability is improved, but the charging capability may be reduced due to increased resistance

Engineering Contradiction:

Improvecycling stabilityVSAvoidcharging capability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The fluorinated additive creates a localized protective layer with specific chemical composition and structure on the negative electrode surface, providing different properties (stability vs. conductivity) at different locations within the interface structure

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 solution effectively prolongs the lifecycle of the negative electrode active material, ensuring cycling stability and improving charging capability by mitigating excessive lithium ion intercalation.

Implementation Method 1

The first additive and the second additive of this application can form stable interfaces on the surfaces of the positive electrode active material and the negative electrode active material

Methodology Applied

Scientific EffectSEI (Solid electrolyte Interface) formation:

Implementation Method 2

which is directly related to the migration ability of lithium ions at the interfaces between positive and negative electrodes, an electrolyte, and their interfaces

Methodology Applied

Scientific EffectLithium ion migration and intercalation: Diffusion

Data Source

PatentEP4625588A1Lithium-ion secondary battery and electric apparatus

Publication Date: 2025.10.01 NINGDE AMPEREX TECHNOLOGY LTD

AI summary

A lithium-ion secondary battery includes an electrolyte, a positive electrode plate, a separator, and a negative electrode plate. The electrolyte includes a first additive and a second additive, based on a mass of the electrolyte, W1% is a mass percentages of the first additive and W2% is a mass percentages of the second additive, 0.05≤W1≤0.8 and 0.01≤W2≤4.1. The negative electrode plate includes a negative electrode current collector and a negative electrode material layer containing a negative electrode active material.