Lithium Battery Positive Electrode Coating for Adhesion and Conductivity
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Solution Overview
Problem
Lithium secondary batteries face challenges in maintaining high capacity and stability when charged and discharged at high electric currents due to increased electrical resistance and peeling of positive and negative electrode materials from the metal foil, leading to internal short circuits and reduced battery life.
Innovation Solution
A positive-electrode material comprising a lithium oxide compound coated with a first type of carbon material and a mixture of two types of fibrous carbon materials with different diameters and lengths, combined with carbon black, to enhance electrical conductivity and adhesion to the metal foil, using a compression shear impact-type particle-compositing technique.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the mean size diameter of the particles of the reactive material is decreased to increase the total reactive surface, then the battery capacity is improved, but the amount of binder required increases and the materials tend to peel from the metal foil
Solution Approach 1:
The patent applies local quality by coating only the surface of the reactive material particles with conductive carbon material, rather than treating the entire particle. This surface coating provides localized adhesion enhancement and electrical conductivity at the critical particle surface, while maintaining the small particle size for high reactive surface area. The coating creates a functional gradient from the core reactive material to the surface coating layer.
Solution Approach 2:
The patent uses composite materials by combining reactive material particles with conductive carbon material coatings and mixing them with fibrous carbon materials. This creates a composite electrode structure where the carbon coating and fibrous carbon work together to provide both adhesion to the metal foil and electrical conductivity, resolving the contradiction between high surface area and reliable attachment.
2Quantity of substance
If the mean size diameter of the particles of the reactive material is decreased to increase the total reactive surface, then the battery capacity is improved, but the electrical resistance increases
Solution Approach 1:
The patent applies local quality by coating only the surface of the reactive material particles with conductive carbon material, rather than treating the entire particle. This surface coating provides localized adhesion enhancement and electrical conductivity at the critical particle surface, while maintaining the small particle size for high reactive surface area. The coating creates a functional gradient from the core reactive material to the surface coating layer.
Solution Approach 2:
The patent uses composite materials by combining reactive material particles with conductive carbon material coatings and mixing them with fibrous carbon materials. This creates a composite electrode structure where the carbon coating and fibrous carbon work together to provide both adhesion to the metal foil and electrical conductivity, resolving the contradiction between high surface area and reliable attachment.
3Quantity of substance
If the positive-electrode and negative-electrode materials are deposited on metal foil to create high capacity batteries, then the battery capacity is improved, but the materials tend to peel or drop from the metal foil leading to internal short circuits
Solution Approach 1:
The patent applies local quality by coating only the surface of the reactive material particles with conductive carbon material, rather than treating the entire particle. This surface coating provides localized adhesion enhancement and electrical conductivity at the critical particle surface, while maintaining the small particle size for high reactive surface area. The coating creates a functional gradient from the core reactive material to the surface coating layer.
Solution Approach 2:
The patent uses composite materials by combining reactive material particles with conductive carbon material coatings and mixing them with fibrous carbon materials. This creates a composite electrode structure where the carbon coating and fibrous carbon work together to provide both adhesion to the metal foil and electrical conductivity, resolving the contradiction between high surface area and reliable attachment.
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 improves electrical resistance properties and adhesion of the electrode materials, resulting in enhanced discharge performance and extended cycle life of lithium secondary batteries.
Implementation Method 1
a first type of carbon material is provided as a coating on the reactive substance particles surface
Implementation Method 2
using a compression shear impact-type particle-compositing technique
Data Source
AI summary
A positive-electrode material for a lithium secondary battery is provided. The material includes a lithium oxide compound or a complex oxide as reactive substance. The material also includes at least one type of carbon material, and optionally a binder. A first type of carbon material is provided as a coating on the reactive substance particles surface. A second type of carbon material is carbon black. And a third type of carbon material is a fibrous carbon material provided as a mixture of at least two types of fibrous carbon material different in fiber diameter and/or fiber length. Also, a method for preparing the material as well as lithium secondary batteries including the material is provided.