Silicon Nanoparticle Negative Electrode for Battery Cycle Stability
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Solution Overview
Problem
Conventional silicon-based negative electrode materials for secondary batteries suffer from rapid deterioration in battery characteristics due to large volume changes, leading to poor initial charging and discharging efficiency and cycle characteristics, making them unsuitable for high-energy density applications.
Innovation Solution
A silicon-based negative electrode material is developed with silicon nanoparticles dispersed in a silicon oxide matrix, exhibiting residual compressive stress, which enhances mechanical and electrochemical properties, including improved hardness, elasticity, and cycle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based negative electrode material is used to achieve high energy density, then discharge capacity increases, but volume change during charging/discharging causes rapid deterioration of battery characteristics
Solution Approach 1:
The silicon-based negative electrode material is divided into nanoparticles with a diameter of 1 nm to 100 nm. This segmentation reduces the overall volume change impact on the electrode structure during lithium insertion and extraction, preventing rapid deterioration while maintaining high discharge capacity of 1200 mAh/g or more
Solution Approach 2:
The invention uses a composite structure where silicon nanoparticles are embedded in a matrix containing silicon oxide and doping elements (alkali metal, alkaline earth metal, or post-transition metal). This composite approach combines the high capacity of silicon with the structural stability of silicon oxide and doping elements, achieving both high discharge capacity and improved cycle characteristics with 95% or more capacity retention after 50 cycles
2Quantity of substance
If silicon-based negative electrode material is used to achieve high energy density, then discharge capacity increases, but initial charging and discharging efficiency deteriorates
Solution Approach 1:
The invention applies local quality by creating a non-uniform structure where silicon nanoparticles are distributed within a silicon oxide matrix containing doping elements. The doping elements are selectively positioned to form conductive networks and stabilize the electrode structure, improving electron and ion transport pathways. This local optimization of material properties achieves initial efficiency of 70% or more while maintaining high discharge capacity
Solution Approach 2:
The invention changes the physical and chemical parameters of the silicon-based material by controlling nanoparticle size (1-100 nm), silicon oxide content (1-50 wt%), and doping element concentration (0.1-10 wt%). These parameter optimizations improve conductivity and reaction kinetics, achieving both high discharge capacity and improved initial charging/discharging efficiency
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 material achieves increased discharge capacity and capacity retention, with a discharge capacity of 1200 mAh/g or more in the first cycle and 95% or more retention after 50 cycles, significantly outperforming conventional silicon-based materials.
Implementation Method 1
a negative electrode material for a secondary battery contains: a matrix containing a silicon oxide, a complex oxide of one or more doping elements selected from the group consisting of an alkali metal, an alkaline earth metal, and a post-transition metal, and silicon, or a mixture thereof; and silicon nanoparticles dispersed and impregnated in the matrix and having residual compressive stress
Data Source
AI summary
Provided is a negative electrode material for a secondary battery. The negative electrode material for a secondary battery contains: a matrix containing a silicon oxide, a complex oxide of one or more doping elements selected from the group consisting of an alkali metal, an alkaline earth metal and a post-transition metal, and silicon, or a mixture thereof; and silicon nanoparticles dispersed and impregnated in the matrix, wherein the negative electrode material for a secondary battery satisfies the following Equation: 1<WN(Si)/WN(ref), wherein WN(ref) is a central wavenumber of a Raman peak of bulk single-crystal silicon, and WN(Si) is a central wavenumber of a Raman peak of nanoparticulate silicon contained in the negative electrode material.