Silicon Anode Composite With S-Mg Silicate for Cycle Retention
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Solution Overview
Problem
Existing silicon-based negative electrode active materials in secondary batteries face challenges in achieving high cycle capacity retention rates and initial coulombic efficiency, necessitating improved electrochemical performance.
Innovation Solution
A silicon-based negative electrode active material containing a combination of element S and element Mg, forming a silicate with an alkali metal element, which enhances the synergistic effect, improving cycle capacity retention and initial coulombic efficiency by alleviating particle expansion and stabilizing the material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based negative electrode active material is used to achieve high capacity, then the battery capacity is improved, but the cycle capacity retention rate deteriorates due to particle expansion
Solution Approach 1:
The patent employs a composite material structure consisting of silicon-based active material particles combined with lithium sulfide (Li2S) and magnesium aluminum silicate (MAS). This composite structure addresses the contradiction by: (1) maintaining the high capacity of silicon-based materials, (2) using Li2S to alleviate particle expansion during cycling, and (3) using MAS to improve initial coulombic efficiency and structural stability, thereby achieving both high capacity and good cycle retention
Solution Approach 2:
The patent introduces lithium sulfide (Li2S) as an intermediary substance that mediates between the silicon-based active material and the electrolyte. Li2S forms a protective interface layer that: (1) reduces direct contact between silicon particles and electrolyte, (2) alleviates particle expansion stress, and (3) improves cycle stability while maintaining electrochemical performance
2Quantity of substance
If silicon-based negative electrode active material is used to achieve high capacity, then the battery capacity is improved, but the initial coulombic efficiency deteriorates
Solution Approach 1:
The patent employs a composite material structure consisting of silicon-based active material particles combined with lithium sulfide (Li2S) and magnesium aluminum silicate (MAS). This composite structure addresses the contradiction by: (1) maintaining the high capacity of silicon-based materials, and (2) using MAS to form a stable interface that improves initial coulombic efficiency by reducing irreversible capacity loss during the first cycle
Solution Approach 2:
The patent modifies the surface and interface parameters of the silicon-based active material by introducing magnesium aluminum silicate (MAS). This parameter change: (1) alters the surface composition and structure, (2) reduces irreversible lithium consumption during initial cycling, and (3) improves initial coulombic efficiency while preserving the high capacity characteristics of silicon-based materials
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 combination of element S and Mg in the silicon-based negative electrode active material significantly improves cycle capacity retention and initial coulombic efficiency, resulting in better battery performance.
Implementation Method 1
a lithium-sulfur compound formed by element S and lithium can alleviate expansion of particles, improve the stability of the material
Implementation Method 2
Element Mg can form a magnesium aluminum silicate with a silicon oxide material, which can effectively improve the initial coulombic efficiency of the battery
Data Source
AI summary
This application provides a silicon-based negative electrode active material. The silicon-based negative electrode active material includes a silicate containing an alkali metal element. The silicon-based negative electrode active material contains both element S and element Mg.