Anode Active Material for Lithium Secondary Battery
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Solution Overview
Problem
Lithium secondary batteries face limitations in power, life-time, and thermal stability due to the use of artificial graphite as an anode active material, which affects battery output and high-temperature storage properties.
Innovation Solution
An anode active material is developed using secondary particles formed from primary artificial graphite particles with specific diameter and orientation ranges, enhancing battery power and life-time while maintaining high-temperature storage properties, achieved by controlling the average diameter of primary particles between 5 μm to 15 μm and agglomerating them into secondary particles with a specific I(110)/I(002) ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If artificial graphite is used as anode active material, then capacity is improved, but power and thermal stability deteriorate
Solution Approach 1:
The artificial graphite is divided into primary particles with average diameter of 5-15 μm, which are then assembled into secondary particles. This segmentation allows control of crystal orientation while maintaining capacity, resolving the contradiction between capacity and power by creating a hierarchical structure where small primary particles provide high capacity and their controlled assembly provides improved power characteristics.
Solution Approach 2:
The invention controls the crystal orientation locally by adjusting the I(110)/I(002) ratio to 0.0075-0.012, creating anisotropic properties in specific directions. This local quality control allows the graphite to exhibit improved power and thermal stability in critical directions while maintaining overall capacity, thus resolving the contradiction between capacity and power.
2Quantity of substance
If artificial graphite is used as anode active material, then capacity is improved, but life-time deteriorates
Solution Approach 1:
By segmenting the artificial graphite into controlled primary particles (5-15 μm) and assembling them into secondary particles with specific crystal orientation (I(110)/I(002) = 0.0075-0.012), the invention creates a structure that maintains capacity while improving life-time. The segmented structure reduces internal stress during lithium insertion/extraction cycles, preventing capacity degradation over time.
3Quantity of substance
If artificial graphite is used as anode active material, then capacity is improved, but thermal stability deteriorates
Solution Approach 1:
The invention applies local quality control by adjusting the crystal orientation of artificial graphite particles, specifically controlling the I(110)/I(002) ratio to 0.0075-0.012. This creates anisotropic thermal properties where the graphite exhibits improved thermal stability in directions critical for battery operation, while maintaining high capacity. The oriented structure provides better thermal management characteristics.
4Quantity of substance
If artificial graphite is used as anode active material, then capacity is improved, but high-temperature storage properties deteriorate
Solution Approach 1:
The segmentation of artificial graphite into primary particles (5-15 μm) assembled into secondary particles with controlled crystal orientation improves high-temperature storage properties. The smaller primary particle size reduces thermal runaway risk, while the controlled assembly into secondary particles maintains structural integrity at elevated temperatures, thus resolving the contradiction between capacity and high-temperature storage properties.
Data Source
AI summary
An anode active material for lithium secondary battery includes a secondary particle formed by agglomerating primary particles, an average diameter of the primary particles is in a range from 5 μm to 15 μm, and an average diameter of the secondary particle is in a range from 10 μm to about 25 μm. The primary particles include an artificial graphite, and an I(110)/I(002) of the secondary particle is in a range from about 0.0075 to 0.012.