Composite Anode Material for Lithium Ion Battery
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Solution Overview
Problem
Lithium ion secondary batteries face limitations in energy density, input-output performance, lifetime characteristics, and thermal stability due to the reactivity of graphite and insufficient energy density of amorphous carbon, particularly at high temperatures.
Innovation Solution
A carbon-based anode material with specific characteristics, including an average interlayer spacing of 0.335 nm to 0.340 nm, particle diameters ranging from 1 μm to 40 μm, and two exothermic peaks between 300°C to 1000°C, is developed to enhance energy density, input-output characteristics, and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If graphite is used as anode material, then high crystallinity and good structure are achieved, but high reactivity with electrolyte solution and poor lifetime characteristics occur
Solution Approach 1:
The invention uses a composite anode material consisting of amorphous carbon particles (5-50 μm) coated with a graphite layer (0.1-10 μm thick). The amorphous carbon core provides low reactivity and good lifetime characteristics, while the graphite coating provides high crystallinity and good structural stability. This composite structure resolves the contradiction between high crystallinity and good lifetime characteristics.
2Stability of the object's composition
If graphite is used as anode material, then good structural stability is achieved, but insufficient input-output performance occurs due to limited intercalation sites
Solution Approach 1:
The composite structure with amorphous carbon core and graphite coating allows the amorphous carbon to provide numerous intercalation sites across the entire particle surface, enabling high input-output performance, while the graphite coating maintains good structural stability.
3Reliability
If amorphous carbon is used as anode material, then low reactivity and good lifetime characteristics are achieved, but insufficient energy density occurs
Solution Approach 1:
The amorphous carbon core provides good lifetime characteristics and low reactivity, while the graphite coating contributes to higher energy density through its ordered structure and efficient lithium ion intercalation capability, resolving the contradiction between lifetime characteristics and energy density.
4Length of stationary object
If graphite is used as anode material, then good interlayer spacing is achieved, but high reactivity at surfaces occurs especially at high temperatures
Solution Approach 1:
The amorphous carbon core provides thermal stability and low reactivity at high temperatures, while the graphite coating maintains good interlayer spacing for lithium ion insertion. The composite structure resolves the contradiction between interlayer spacing and reactivity.
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 anode material achieves a balance of high energy density, excellent input-output characteristics, and improved thermal stability, making it suitable for applications in electric vehicles and other high-power devices.
Implementation Method 1
intercalation or deintercalation of lithium ions proceeds at end portions of the stacked network planes, thereby causing charging and discharging
Implementation Method 2
at least two exothermic peaks within a temperature range of from 300° C. to 1000° C. in a differential thermal analysis in an air stream
Data Source
AI summary
An anode material for a lithium ion secondary battery that includes a carbon material having an average interlayer spacing d002 as determined by X-ray diffraction of from 0.335 nm to 0.340 nm, a volume average particle diameter (50% D) of from 1 μm to 40 μm, a maximum particle diameter Dmax of 74 μm or less, and at least two exothermic peaks within a temperature range of from 300° C. to 1000° C. in a differential thermal analysis in an air stream.