Silicon Oxide Particles with Iron Gradient for Battery Cycle Life
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Solution Overview
Problem
Silicon oxide-based active materials for negative electrodes in nonaqueous electrolyte secondary batteries are expensive and have inferior cycle performance, making them unsuitable for automotive applications despite offering high battery capacity and low volume expansion.
Innovation Solution
Silicon oxide particles with a specific iron content distribution and average particle size are used as negative electrode active material, prepared by heating a feed material in an inert gas and grinding to achieve improved cycle performance and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon oxide-based active material is used as negative electrode material, then battery capacity is improved and volume expansion is reduced, but cycle performance deteriorates and manufacturing cost increases
Solution Approach 1:
The invention applies local quality by creating a non-uniform iron content distribution within the silicon oxide particles. The inner portion contains 10-1000 ppm iron while the outer portion contains up to 30 ppm iron. This localized variation in composition optimizes different regions for different functions: the inner portion provides structural stability for cycle performance, while the outer portion maintains high reactivity for battery capacity.
Solution Approach 2:
The invention changes the chemical composition parameters of silicon oxide by controlling iron content within specific ranges (10-1000 ppm inner portion, up to 30 ppm outer portion). This parameter optimization resolves the contradiction by finding the optimal iron concentration that simultaneously improves cycle performance while maintaining high battery capacity.
2Quantity of substance
If silicon oxide-based active material is used as negative electrode material, then battery capacity is improved and volume expansion is reduced, but manufacturing cost increases
Solution Approach 1:
The invention optimizes manufacturing by specifying precise iron content ranges (10-1000 ppm inner, up to 30 ppm outer) that can be achieved through controlled synthesis processes. These parameter specifications enable standardized production methods that reduce manufacturing complexity and cost while maintaining high battery capacity.
3Reliability
If iron content is increased in silicon oxide particles, then cycle performance is improved, but battery capacity may be compromised
Solution Approach 1:
The invention resolves this contradiction by applying local quality through spatially differentiated iron distribution. The inner portion (10-1000 ppm iron) provides cycle performance enhancement, while the outer portion (up to 30 ppm iron) maintains high reactivity and capacity. This localized composition optimization allows both requirements to be satisfied simultaneously.
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 oxide particles enhance the cycle performance and capacity of nonaqueous electrolyte secondary batteries, making them suitable for automotive applications while maintaining low volume expansion and reducing manufacturing costs.
Implementation Method 1
heating the feed material in an inert gas under normal or reduced pressure at a temperature in the range of 1,100 to 1,600° C. to generate a SiO gas
Implementation Method 2
cooling the gas for deposition
Data Source
AI summary
Silicon oxide particles each comprising an inner portion having an iron content of 10-1,000 ppm and an outer portion having an iron content of up to 30 ppm are suitable as negative electrode active material in nonaqueous electrolyte secondary batteries. Using a negative electrode comprising the silicon oxide particles as active material, a lithium ion secondary battery or electrochemical capacitor having a high capacity and improved cycle performance can be constructed.