Multilayer Graphite Negative Electrode for Adhesion and Capacity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face challenges in achieving high capacity and stability due to electrode separation issues caused by inadequate adhesion between electrode components, which is exacerbated by the use of binders and conductive materials, leading to decreased performance and capacity.
Innovation Solution
A multilayer negative electrode structure is introduced, featuring a first layer with natural graphite for improved adhesion to the current collector and a second layer with artificial graphite for enhanced output and lifespan characteristics, allowing for sufficient adhesion with a reduced binder content and maintaining high capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large amount of electrode active material is disposed on the current collector to achieve high capacity, then the battery capacity increases, but the electrode adhesion deteriorates causing electrode separation
Solution Approach 1:
The electrode is divided into multiple layers with different active material compositions. The first layer contains natural graphite particles providing strong adhesion to the current collector, while the second layer contains artificial graphite particles providing high capacity. This segmentation allows each layer to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the electrode are assigned different material compositions tailored to their functional requirements. The layer adjacent to the current collector uses natural graphite with superior adhesion properties, while the outer layer uses artificial graphite with higher capacity density, optimizing both adhesion and capacity locally.
2Reliability
If binder content is increased to improve electrode adhesion, then the electrode adhesion improves, but the internal resistance increases and electronic conductivity decreases
Solution Approach 1:
The natural graphite particles in the first layer inherently provide strong adhesion to the current collector without requiring excessive binder. This self-adhesive property of natural graphite reduces the need for additional binder materials, thereby maintaining good electronic conductivity while achieving sufficient adhesion.
3Power
If conductive material content is increased to improve output characteristic, then the electronic conductivity improves, but the adhesion is lowered and the amount of active material decreases
Solution Approach 1:
The electrode structure is segmented into two layers where the first layer with natural graphite provides the adhesion function, and the second layer with artificial graphite provides the high capacity and output characteristics. This functional segmentation eliminates the need to compromise adhesion for output performance.
4Power
If artificial graphite is used to improve output characteristics and lifespan, then the output and lifespan improve, but the adhesion to current collector deteriorates
Solution Approach 1:
The electrode is segmented into two distinct layers: the first layer contains natural graphite particles that provide strong adhesion to the current collector, while the second layer contains artificial graphite particles that provide excellent output characteristics and lifespan. This segmentation allows artificial graphite to be used extensively for high performance without compromising adhesion.
Solution Approach 2:
The electrode structure implements local quality optimization by placing natural graphite specifically at the interface with the current collector where adhesion is critical, while using artificial graphite in the bulk electrode where output characteristics and lifespan are most important.
Data Source
AI summary
The present disclosure relates to a multilayer negative electrode comprising a negative electrode current collector configured to transfer electrons between an outer lead and a negative electrode active material, a first negative electrode mixture layer formed on one surface or both surfaces of the current collector and containing natural graphite as a negative electrode active material and a second negative electrode mixture layer formed on the first negative electrode mixture layer and containing artificial graphite as a negative electrode active material, and a lithium secondary battery including the same.