Lithium Silicon Oxide Composite for Low-Gas Aqueous Slurry Processing
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Solution Overview
Problem
The preparation of a silicon-based negative electrode material for lithium secondary batteries using a water-based process leads to viscosity changes and hydrogen generation due to the reaction of LiOH byproducts, resulting in reduced adhesion and capacity issues.
Innovation Solution
A method involving the preparation of a lithium silicon oxide composite by adding silicon or silicon oxide to a lithium compound-containing solution with a specific concentration, stirring in an inert gas atmosphere, and sintering the particles to form a composite that suppresses viscosity changes and hydrogen generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicon oxide particles are prelithiated with lithium to improve initial efficiency, then initial capacity is improved, but Li2O reacts with H2O to form LiOH byproduct causing viscosity reduction and hydrogen generation
Solution Approach 1:
The patent changes the concentration parameter of the lithium compound-containing solution to a specific range (0.5-1.5 M) to control the reaction between Li2O and H2O, thereby suppressing hydrogen generation while maintaining initial capacity improvement
Solution Approach 2:
The patent creates a composite material structure by forming lithium silicate compounds through the reaction of prelithiated silicon oxide with lithium compound-containing solution, where the resulting composite suppresses both hydrogen generation and viscosity changes
2Reliability
If silicon oxide particles are prelithiated with lithium to improve initial efficiency, then initial capacity is improved, but coating properties are deteriorated due to viscosity reduction
Solution Approach 1:
The patent controls the concentration parameter of the lithium compound-containing solution within 0.5-1.5 M range to minimize viscosity changes during slurry preparation, thereby maintaining good coating properties while achieving improved initial capacity
Solution Approach 2:
The formation of lithium silicate composite structure suppresses excessive viscosity reduction, maintaining slurry stability and coating properties while preserving the initial capacity benefits of prelithiation
3Stability of the object's composition
If graphite-based negative electrode material is used, then structural stability is excellent, but theoretical capacity is low (350 mAh/g)
Solution Approach 1:
The patent creates a composite negative electrode material combining silicon oxide with lithium compound-containing solution to form lithium silicate structures, achieving high theoretical capacity (2700-4200 mAh/g) while maintaining structural stability through the composite structure
4Quantity of substance
If silicon-based negative electrode material is used, then theoretical capacity is high (2700-4200 mAh/g), but volume expansion occurs during charge and discharge
Solution Approach 1:
The patent forms a composite structure where silicon oxide reacts with lithium compound-containing solution to create lithium silicate phases, which have more stable volume characteristics during charge-discharge cycles while maintaining high theoretical capacity
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 method produces a lithium silicon oxide composite with excellent initial capacity and capacity retention, preventing coating defects and adhesion issues, suitable for use as a negative electrode material.
Implementation Method 1
adding silicon or silicon oxide to a lithium compound-containing solution having a concentration of greater than 0.5 M and less than 1.0 M, in which the lithium-containing compound is dissolved
Implementation Method 2
a method of preparing a lithium silicon oxide composite that is useful as a negative electrode material in which there is almost no change in viscosity and hydrogen generation is suppressed
Implementation Method 3
sintering the particles to form a composite
Data Source
AI summary
The present invention relates to a method of preparing a lithium silicon oxide composite in which gas generation is suppressed when an aqueous slurry is used, wherein the present invention provides the method of preparing a lithium silicon oxide composite which includes steps of adding silicon or silicon oxide (SiOx, 0<x≤ 2) to a lithium compound-containing solution and stirring the solution in an inert gas atmosphere (S1); and separating particles formed, and drying and sintering the particles (S2), wherein a concentration of the lithium compound-containing solution is greater than 0.5 M and less than 1.0 M.