Lithium-ion secondary battery
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Solution Overview
Problem
Lithium-ion secondary batteries, particularly all-solid-state lithium-ion secondary batteries, face challenges in achieving improved high-rate charging and discharging performance due to the formation of a solid electrolyte interphase with higher resistance and incomplete penetration of the solid electrolyte, which degrades lithium-ion diffusivity in the anode body layer.
Innovation Solution
The battery incorporates graphite particles with a specific crystallite size ratio of the (004) plane to the (110) plane, measured by X-ray crystal diffraction using CuKα rays, of 0.683 or more, which enhances lithium diffusibility on the surface and within the anode active material, improving charging and discharging performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid electrolyte is used in the anode body layer, then battery safety and stability are improved, but lithium-ion diffusivity deteriorates due to higher resistance and incomplete penetration
Solution Approach 1:
The patent changes the crystal structure parameters of graphite particles by controlling the crystallite size ratio of (004) plane to (110) plane to be 0.683 or more. This parameter change in the anode active material's crystal structure improves lithium-ion diffusivity within the graphite particles, compensating for the reduced diffusivity caused by solid electrolyte resistance, thereby maintaining high-rate charging and discharging performance while using solid electrolyte for safety.
2Productivity
If graphite particles with specific crystallite size ratio are used, then lithium-ion diffusivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a quantitative parameter (crystallite size ratio of (004) plane to (110) plane ≥ 0.683) that can be measured and controlled using standard X-ray diffraction techniques. This provides a clear manufacturing target that balances performance improvement with manufacturability, allowing producers to achieve the desired lithium-ion diffusivity through controlled graphitization processes while using conventional measurement and quality control methods.
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 graphite particles with the specified crystallite size ratio significantly improves lithium-ion diffusibility, leading to enhanced high-rate charging and discharging performance in lithium-ion secondary batteries.
Implementation Method 1
the anode active material is graphite particles having a ratio of a crystallite size of a (004) plane to a crystallite size of a (110) plane... lithium diffusibility on the surface and within the anode active material
Implementation Method 2
measured by X-ray crystal diffraction measurement using CuKα rays
Data Source
AI summary
A lithium-ion secondary battery of the present disclosure includes a cathode body layer, a separator layer, and an anode body layer in that order, wherein the anode body layer contains a solid electrolyte and an anode active material, and wherein the anode active material is graphite particles having a ratio of a crystallite size of a (004) plane to a crystallite size of a (110) plane (the crystallite size of the (004) plane/the crystallite size of the (110) plane) measured by X-ray crystal diffraction measurement using CuKα rays of 0.683 or more.