Non-graphitizable Carbon Anode Density via Mechanochemical Treatment
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Solution Overview
Problem
Conventional non-graphitizable carbon materials used as negative electrode materials in lithium ion secondary batteries exhibit insufficient electrode density, which is a concern as there is a trend towards reducing the size of these batteries and requiring higher density materials.
Innovation Solution
A method involving a cross-linking treatment using an air blowing reaction, followed by an infusibilizing treatment and a mechanochemical treatment to produce a non-graphitizable carbon material with increased electrode density, involving the use of pitches as raw materials and applying oxidizing gases to enhance the material's properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional non-graphitizable carbon materials are used as negative electrode materials, then the battery can operate with basic performance, but the electrode density is insufficient
Solution Approach 1:
The patent creates a composite material structure by combining non-graphitizable carbon material with graphite particles (0.1-10 μm in size) on the surface. This composite approach allows the core to provide high density while the surface graphite layer ensures reliable lithium ion insertion/extraction, resolving the contradiction between density and performance adequacy
Solution Approach 2:
The patent applies different properties to different parts of the carbon material: the internal core region consists of dense non-graphitizable carbon for high electrode density, while the surface layer contains graphite particles for reliable electrochemical performance. This local differentiation resolves the contradiction by optimizing each region for its specific function
2Volume of moving object
If the electrode density is increased to reduce battery size, then the battery volume decreases, but the mechanical damage to current collectors and separators increases
Solution Approach 1:
The patent changes the particle size parameter of graphite to specifically 0.1-10 μm, which is small enough to fit within the expanded non-graphitizable carbon structure without causing excessive mechanical stress. This precise parameter control allows high density while minimizing damage to current collectors and separators
Solution Approach 2:
The patent utilizes the porous expanded structure of non-graphitizable carbon material to accommodate graphite particles and lithium ions. The porous architecture provides buffering space that reduces mechanical stress during volume changes, preventing damage to battery components while maintaining high density
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 method results in a non-graphitizable carbon material with higher electrode density, suitable for lithium ion secondary batteries, improving their performance and safety by reducing damage to current collectors and separators.
Implementation Method 1
a cross-linking treatment which is a method utilizing an air blowing reaction being a liquid state reaction in which the softening point of the raw material is increased by heating the raw material and by blowing an oxidizing gas selected from the group consisting of air, oxygen, ozone, and a mixture of these gases into the raw material
Implementation Method 2
a process of obtaining a non-graphitizable carbon material by baking the infusibilized product, in which a mechanochemical treatment is performed on the cross-linked product or the infusibilized product
Data Source
Figure 1~2
Figure 3(a)~3(b)
AI summary
A method for producing a non-graphitizable carbon material is provided. The method includes a process of obtaining a cross-linked product by performing a cross-linking treatment on a raw material of a hardly ⇒ non-graphitizable carbon material, a process of obtaining an infusibilized product by performing an infusibilizing treatment on the cross-linked product, and a process of obtaining a non-graphitizable carbon material by baking the infusibilized product, in which a mechanochemical treatment is performed on the cross-linked product or the infusibilized product.