Multi-Layer Silicon Anode for Lithium Battery

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Solution Overview

Problem

Lithium secondary batteries face challenges in achieving high capacity and low resistance due to the use of silicon-based anode active materials, which often result in increased electrical resistance and limited cycle life.

Innovation Solution

A multi-layered anode structure is developed, comprising a primer layer, a first anode active material layer, and a second anode active material layer, with a higher ratio of silicon-based active material in the second layer, utilizing silicon-based active materials and carbon-based materials, and specific binders to enhance adhesion and stability, and a method of fabricating this structure to improve electrical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If silicon-based anode active material is used to increase capacity, then the battery capacity is improved, but the electrical resistance increases

Engineering Contradiction:

Improvebattery capacityVSAvoidelectrical resistance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The anode active material layer is divided into multiple layers with different silicon-based active material contents. The first layer has a lower silicon content (1-10 wt%) while the second layer has a higher silicon content (11-30 wt%), creating a gradient structure that balances capacity and conductivity throughout the electrode thickness

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the anode active material layer are assigned different silicon-based active material contents to optimize local properties. The first layer near the current collector has lower silicon content for better conductivity, while the second layer has higher silicon content for maximum capacity utilization

Inventive Principle:

Principle #3Local quality

2Reliability

If multi-layered anode structure is created to improve electrical properties, then the manufacturing complexity increases

Engineering Contradiction:

Improveelectrical resistanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

A primer layer is formed on the current collector surface before applying the anode active material layers. This primer layer improves adhesion and facilitates the subsequent coating process, making the multi-layer structure easier to manufacture

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Multiple functional layers (primer layer, first anode active material layer, second anode active material layer) are combined into a single integrated anode structure that can be manufactured in one continuous coating and drying process

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentEP4187631A1Anode for lithium secondary battery, method of fabricating the same and lithium secondary battery including the same

Publication Date: 2023.05.31 SK ON CO LTD

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AI summary

An anode for a lithium secondary battery according to an embodiment of the present invention includes an anode current collector, a primer layer formed on a surface of the anode current collector, and an anode active material layer including a first anode active material layer and a second anode active material layer sequentially disposed on the primer layer. Each of the first anode active material layer and the second anode active material layer includes a silicon-based active material. A ratio of a content of the silicon-based active material in the second anode active material layer relative to a content of the silicon-based active material in the first anode active material layer among a total content of the silicon-based active material included in the anode active material layer is greater than 1.25 and less than 5.