Silicon Nanoparticle-Coated SiOx Anode for Lithium Battery
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Solution Overview
Problem
Lithium secondary batteries face issues with low reversibility and safety due to lithium metal anodes, and carbon-based anodes have limited capacity and volume change problems, while non-carbon materials like SiOx suffer from irreversible reactions and challenging charge-discharge cycle characteristics.
Innovation Solution
A non-carbon-based anode active material for lithium secondary batteries is developed, featuring a silicon-containing core with silicon nanoparticles and a carbon coating, which reduces initial irreversible reactions and volume expansion, enhancing charge-discharge cycle efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon (Si) is used as anode active material to achieve high capacity, then charge-discharge capacity is improved, but volume change during charging-discharging causes active material layer cracking and rapid capacity decrease
Solution Approach 1:
The silicon anode active material is divided into fine particles with a maximum particle size of 10 μm. This segmentation reduces the overall volume change impact during charging-discharging cycles, preventing cracks in the active material layer and maintaining capacity retention.
Solution Approach 2:
The patent changes the particle size parameter of silicon to optimize performance. By controlling the maximum particle size to 10 μm or less, the invention achieves a balance between high capacity and minimal volume expansion effects during cycling.
2Quantity of substance
If non-carbon material such as SiO is used as anode active material to achieve high capacity and controlled volume expansion, then capacity characteristics are improved, but by-products from Li and O reaction cause irreversible reaction and lower initial efficiency
Solution Approach 1:
The patent changes the oxygen content parameter by controlling the SiOx composition with 0 < x ≤ 0.5. This parameter optimization reduces irreversible reactions between Li and O, minimizing by-product formation and improving initial efficiency while maintaining high capacity characteristics.
3Reliability
If carbon material is used as anode active material to achieve small volume change and excellent reversibility, then safety and reversibility are improved, but capacity is inferior to lithium metal and limited
Solution Approach 1:
The patent creates a composite anode active material consisting of silicon particles (maximum 10 μm) mixed with conductive carbon material. This composite structure combines the high capacity of silicon with the electrical conductivity and structural stability of carbon, achieving both high capacity and good reversibility.
4Quantity of substance
If SiOx is used as anode active material to overcome irreversible reaction issues, then capacity is improved, but charge-discharge cycle characteristics cannot be sufficiently improved and x value cannot be easily adjusted by conventional synthesis method
Solution Approach 1:
The patent achieves easy adjustment of the x value in SiOx by controlling the oxidation process parameters. By varying oxidation time, temperature, and atmosphere, the x value can be precisely controlled within 0 < x ≤ 0.5, enabling easy manufacturing adjustment without complex synthesis 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 silicon nanoparticle-coated SiOx core with a carbon layer improves adhesivity and conductivity, reducing volume expansion and increasing the initial efficiency and capacity of lithium secondary batteries.
Implementation Method 1
a silicon-containing core provided on the surface thereof with silicon nanoparticles
Implementation Method 2
improves adhesivity and conductivity
Data Source
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AI summary
Disclosed herein is a non-carbon-based anode active material for lithium secondary batteries, including: a core containing silicon (Si); and silicon nanoparticles formed on the surface of the core. The non-carbon-based anode active material is advantageus in that the increase in the volume expansion during charging-discharging can be prevented by the application of silicon nanoparticles, and in that SiOx(x < 1.0) can be easily prepared.