Anode Active Material Using Natural and Mosaic Coke Graphite
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Solution Overview
Problem
Lithium secondary batteries face challenges with high interfacial resistance and low rate performance due to the limitations of existing anode active materials, such as spherical natural graphite, which results in inefficient lithium ion intercalation and deintercalation, and increased electrode resistance.
Innovation Solution
An anode active material comprising a combination of natural graphite and mosaic coke-based artificial graphite is used, which facilitates lithium ion intercalation and deintercalation and enhances conductivity, reducing interfacial resistance and improving rate performance without the need for additional conductive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If spherical natural graphite is used as anode active material, then the battery structure is simple, but the ionic conductivity is limited and empty spaces are created between active materials increasing electrode resistance
Solution Approach 1:
The patent uses a composite anode active material consisting of spherical natural graphite particles combined with flake-shaped artificial graphite particles. This composite structure maintains the simplicity of using spherical particles while the flake-shaped artificial graphite fills empty spaces between natural graphite particles, improving ionic conductivity and reducing electrode resistance without complicating the battery structure.
2Stability of the object's composition
If flake-shaped graphite with highly developed layer structure is used, then the degree of graphitization is high, but the edge surfaces are small and high rate discharge characteristic is deteriorated
Solution Approach 1:
The patent applies local quality by using spherical natural graphite particles which have uniformly distributed surface areas, eliminating the problem of small edge surfaces in flake-shaped graphite. The spherical morphology provides numerous interstitial spaces that facilitate lithium ion insertion and extraction, improving high rate discharge characteristics while maintaining appropriate graphitization levels.
3Quantity of substance
If hard carbon is used as anode material, then the reversible capacity is high due to micropores, but the initial efficiency is low and irreversible consumption of lithium is significant
Solution Approach 1:
The patent creates a composite anode material where spherical natural graphite particles (with good initial efficiency) are combined with flake-shaped artificial graphite particles (with high reversible capacity). This composite structure achieves both high reversible capacity and acceptable initial efficiency by distributing lithium storage between the two material types, reducing irreversible lithium consumption compared to using hard carbon alone.
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 use of natural graphite and mosaic coke-based artificial graphite in the anode active material improves the rate performance and reduces interfacial resistance of lithium secondary batteries, leading to enhanced conductivity and energy density, even without additional conductive materials.
Implementation Method 1
facilitates lithium ion intercalation and deintercalation
Data Source
AI summary
The present invention relates to an anode active material including natural graphite and mosaic coke-based artificial graphite, and a lithium secondary battery including the same. According to an embodiment of the present invention, an anode active material including natural graphite and mosaic coke-based artificial graphite is used, when applied to a lithium secondary battery, intercalation and deintercalation of lithium ions is more facilitated and conductivity of an electrode is improved even if no or little conductive material is used. Furthermore, the increase in conductivity can lead to not only a further improvement in rate performance of a lithium secondary battery but also a reduction in interfacial resistance.