Silicon-Oxygen Anode Structure for Low-Swelling Li-Ion Batteries
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Solution Overview
Problem
Lithium-ion batteries experience volumetric swelling and contraction during charge and discharge cycles due to silicon materials' intercalation and deintercalation, leading to increased electrolyte consumption and reduced cycling performance.
Innovation Solution
A secondary battery with a negative electrode plate containing a silicon-oxygen composite material, where the ratio of peak intensities in differential thermogravimetry curves and Raman spectra is controlled, and a core-shell structure with amorphous carbon and metal oxide layers is used to reduce side reactions and electrolyte consumption, enhancing initial coulombic efficiency and cycling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon materials are used in lithium-ion batteries to achieve high theoretical gram capacity, then energy density is improved, but volumetric swelling and contraction occur during charge and discharge cycles, leading to increased electrolyte consumption and reduced cycling performance
Solution Approach 1:
The patent employs a composite material structure consisting of silicon-oxygen composite material (containing silicon grains and lithium silicate) as the core, combined with amorphous carbon coating and metal oxide shell. This composite structure allows the battery to achieve high energy density from the silicon content while the oxygen-containing groups and shell structure mitigate swelling and reduce electrolyte consumption, thereby improving cycling performance
Solution Approach 2:
The patent uses amorphous carbon as a coating layer and metal oxide as a shell structure around the silicon-oxygen composite material. These flexible shell structures accommodate the volumetric changes of silicon during lithium intercalation and deintercalation, preventing direct contact between silicon and electrolyte, thus reducing electrolyte consumption and improving cycling performance
2Quantity of substance
If silicon materials undergo intercalation and deintercalation of lithium ions to provide high capacity, then energy storage capability is improved, but volumetric swelling and contraction result in increased electrolyte consumption
Solution Approach 1:
The amorphous carbon coating and metal oxide shell form a protective barrier around the silicon-oxygen composite material. This shell structure allows lithium ion transport while preventing direct contact between silicon and electrolyte, thereby maintaining high capacity through silicon's intercalation capability while significantly reducing electrolyte consumption
Solution Approach 2:
The metal oxide shell and amorphous carbon layer act as intermediary substances between silicon and electrolyte. They facilitate lithium ion transport while preventing harmful direct reactions, thus enabling high capacity utilization while minimizing electrolyte consumption
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 solution improves the rate performance, cycling performance, and swelling resistance of the secondary battery, maintaining high energy density and extending its service life.
Implementation Method 1
during a charge and discharge cycle, with intercalation and deintercalation of lithium ions, silicon materials experience volumetric swelling and contraction
Implementation Method 2
A peak intensity of a differential thermogravimetry curve of the negative electrode plate at 500° C. to 700° C. is Y1
Implementation Method 3
a peak intensity of a Raman spectrum of the negative electrode plate at 1200 cm−1 to 1500 cm−1 is I1
Data Source
AI summary
A secondary battery includes a negative electrode plate. The negative electrode plate includes a negative electrode current collector and a negative electrode active substance layer provided on at least one surface of the negative electrode current collector. The negative electrode active substance layer includes a negative electrode active substance. The negative electrode active substance includes a silicon-oxygen composite material. A peak intensity of a differential thermogravimetry curve of the negative electrode plate at 500° C. to 700° C. is Y1, and a peak intensity of the differential thermogravimetry curve of the negative electrode plate at 350° C. to 450° C. is Y2, where 0.1≤Y1/Y2≤4.