Pre-Lithiated SiOx Anode Material to Prevent Particle Cracking
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Solution Overview
Problem
Silicon-based negative electrode active materials for lithium secondary batteries face challenges such as particle cracking due to high expansion rates during charging and discharging, leading to reduced initial efficiency and lifetime characteristics.
Innovation Solution
A pre-lithiated silicon oxide-based complex containing Al, Li, and Si is formed by mixing and heat-treating silicon oxide with aluminum to create compounds like Al2O3 and Li2SiO3, which prevent cracking and enhance initial efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon oxide-based negative electrode active material is used to increase discharge capacity, then energy density is improved, but particle cracking occurs due to shrinkage and expansion during charging and discharging
Solution Approach 1:
The patent uses a composite material system consisting of silicon oxide (SiOx) combined with aluminum (Al) and lithium (Li) compounds. This composite structure allows the material to maintain high discharge capacity while the aluminum and lithium compounds form a protective matrix that prevents particle cracking during volume expansion and contraction cycles.
Solution Approach 2:
The patent changes the chemical composition parameters by incorporating aluminum and lithium compounds into the silicon oxide structure. This parameter modification transforms the material properties, enabling it to accommodate volume changes without cracking while maintaining high capacity.
2Quantity of substance
If pre-lithiation techniques are applied to increase initial efficiency, then initial charge capacity is improved, but lifetime characteristics deteriorate due to formation of silicon oxide-based compounds
Solution Approach 1:
The patent modifies the chemical composition by adding aluminum and lithium compounds during pre-lithiation. This parameter change allows the formation of a stable composite structure that provides both high initial charge capacity and improved lifetime characteristics, overcoming the deterioration issue of conventional pre-lithiation methods.
Solution Approach 2:
By creating a composite material system with silicon oxide, aluminum, and lithium compounds, the patent achieves a balance between initial efficiency and long-term stability. The composite structure prevents the harmful effects of pure silicon oxide compound formation while maintaining pre-lithiation benefits.
3Reliability
If graphite is used as negative electrode material to ensure stable structure, then reliability is improved, but discharge capacity per weight is limited to 372 mAh/g
Solution Approach 1:
The patent creates a composite material that combines the high capacity of silicon oxide (3579 mAh/g) with the structural stability provided by aluminum and lithium compounds. This composite approach overcomes graphite's capacity limitation while maintaining structural integrity through the protective matrix.
Solution Approach 2:
The patent applies local quality by having different components perform different functions: silicon oxide provides high capacity, while aluminum and lithium compounds provide structural stability and crack prevention. This functional differentiation achieves both high capacity and reliability.
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 effectively prevents particle cracking, improves initial charge capacity, discharge capacity, and retention, thereby enhancing the battery's performance and lifetime.
Implementation Method 1
which have the effect of preventing the silicon oxide-containing (or silicon oxide-based) negative electrode active material from cracking, which occurs due to shrinkage and expansion of the silicon oxide-containing negative electrode active material during charging and discharging
Implementation Method 2
A pre-lithiated silicon oxide-based complex containing Al, Li, and Si is formed by mixing and heat-treating silicon oxide with aluminum
Data Source
AI summary
Provided is a lithium secondary battery negative electrode active material including a pre-lithiated silicon oxide-based complex containing Al, Li, and Si. More particularly, the present disclosure relates to a lithium secondary battery negative electrode active material and a production method thereof in which aluminum (Al) is additionally mixed and heat treated during pre-lithiation of a silicon oxide-based negative electrode active material, such as SiOx(0<x<2), to form compounds, such as Al2O3 and Li2SiO3, which have the effect of preventing the silicon oxide-based negative electrode active material from cracking, which occurs due to shrinkage and expansion of the silicon oxide-based negative electrode active material during charging and discharging of a battery.