Carbonaceous Negative Electrode Material for Li-Ion Batteries
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Solution Overview
Problem
Graphite-based carbonaceous materials used in lithium-ion secondary batteries exhibit high energy density but limited high-speed charge and discharge characteristics due to their high crystallinity, which restricts the diffusion of solvated lithium ions.
Innovation Solution
A stock oil composition comprising a specific ratio of saturated, aromatic, resin, and asphaltene components, derived from residue fluid catalytic cracking apparatus, is used to produce a carbonaceous material with a developed crystal structure, facilitating the formation of diffusion paths for lithium ions through thermal cracking and polymerization, resulting in improved charge and discharge characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If graphite-based carbonaceous material with high crystallinity is used as negative electrode material, then energy density per unit volume increases, but high-speed charge and discharge characteristics deteriorate due to limited diffusion of solvated lithium ions
Solution Approach 1:
The invention changes the crystallinity parameter of the graphite-based carbonaceous material from high to low through controlled carbonization processes, thereby transforming the material properties to enable faster lithium ion diffusion while maintaining adequate energy density for practical applications
Solution Approach 2:
The invention creates a composite structure by combining graphite-based carbonaceous material with amorphous carbonaceous material in specific ratios (graphite 20-80 wt%, amorphous carbon 20-80 wt%), where the amorphous component provides fast ion diffusion pathways while the graphite component contributes to energy 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 optimized carbonaceous material achieves excellent high-speed charge and discharge characteristics, enhancing the performance of lithium-ion secondary batteries, particularly in applications like hybrid vehicles.
Implementation Method 1
a heavy oil is treated at high temperature to cause thermal cracking and polymerization and/or condensation reaction
Implementation Method 2
a heavy oil is treated at high temperature to cause thermal cracking and polymerization and/or condensation reaction
Implementation Method 3
high crystallinity of the graphite-based carbonaceous material which limits the diffusion of solvated lithium ions in the carbon layer
Data Source
AI summary
Provided is a stock oil composition for a carbonaceous material for a negative electrode of a lithium-ion secondary battery which composition is useful for achieving excellent high-speed charge and discharge characteristics. The stock oil composition for a carbonaceous material for a negative electrode of a lithium-ion secondary battery uses a bottom oil of residue fluid catalytic cracking apparatus as a raw material. The stock oil composition comprises, of a saturated component, an aromatic component, a resin component and an asphaltene component detectable by development of the stock oil composition using thin-layer chromatography, the saturated component ranging from 30 to 50% by weight and the aromatic component ranging from 50 to 70% by weight; and has an average molecular weight of from 400 to 600.