Amorphous-Coated Graphite Anodes for Fast-Charging Li-Ion Batteries
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Solution Overview
Problem
Carbon materials with an orientation parameter intensity ratio I(002)/I(110) greater than 1200 in negative electrodes of secondary batteries exhibit high diffusion resistance and poor rapid charging characteristics.
Innovation Solution
A carbon material composed of natural graphite coated with an amorphous carbonaceous substance, with an orientation parameter intensity ratio I(002)/I(110) ranging from 200 to 1200, is used in the negative electrode, along with specific manufacturing steps to form an active material layer on a metal current collector, optimizing the electrode structure for improved lithium ion diffusibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a carbon material with an orientation parameter intensity ratio I(002)/I(110) greater than 1200 is used in a negative electrode, then the electrode structure becomes highly oriented, but the diffusion resistance increases and rapid charging characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by controlling the orientation parameter intensity ratio I(002)/I(110) within a specific range of 100 to 1200, rather than allowing it to exceed 1200. This parameter optimization resolves the contradiction by finding the optimal balance point where the electrode maintains sufficient orientation for structural integrity while preventing excessive orientation that would cause high diffusion resistance and poor rapid charging characteristics.
2Stability of the object's composition
If the orientation parameter intensity ratio I(002)/I(110) is increased to improve electrode structure, then the structural order improves, but the lithium ion diffusibility perpendicular to the current collector decreases
Solution Approach 1:
The patent optimizes the orientation parameter intensity ratio I(002)/I(110) to fall within 100 to 1200, which maintains adequate structural order while ensuring sufficient lithium ion diffusibility. This parameter control prevents the structural order from becoming excessive, which would otherwise block lithium ion transport paths perpendicular to the current collector.
3Quantity of substance
If a highly oriented carbon material is used to enhance electrode performance, then the electrode capacity increases, but the rapid charging characteristics worsen
Solution Approach 1:
The patent achieves optimal electrode capacity and rapid charging characteristics by controlling the orientation parameter intensity ratio I(002)/I(110) within 100 to 1200. This parameter optimization ensures that the electrode has sufficient capacity while maintaining open diffusion paths that enable rapid charging, resolving the contradiction between capacity and charging speed.
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 carbon material suppresses diffusion resistance and enhances rapid charging characteristics of secondary batteries by ensuring excellent lithium ion diffusibility perpendicular to the current collector.
Implementation Method 1
the diffusion resistance of the secondary battery is suppressed, and the rapid charging characteristics of the secondary battery are improved
Data Source
AI summary
An object of the present invention is to provide: a carbon material that suppresses diffusion resistance of the secondary battery and improves rapid charging characteristics of the secondary battery when the carbon material is used in a negative electrode of the secondary battery; and a method for manufacturing the carbon material. The present invention relates to a carbon material containing graphite particles. The graphite particles are natural graphite coated with an amorphous carbonaceous substance. Moreover, in an electrode fabricated by adding a binder resin and a dispersion medium to the carbon material to form a slurry, applying the slurry to a metal current collector, drying the applied slurry to form an active material layer on the metal current collector, and then pressing the active material layer such that the active material layer has a density of 1.65 g/cm3, an orientation parameter intensity ratio I(002)/I(110) calculated from an intensity ratio of peaks corresponding to lattice planes (110) and (002), and I(002) and I(110) are obtained by a wide-angle X-ray diffraction measurement, is from 200 to 1200.