Lithium-Doped SiOx Anode Material With Residual Lithium Removal
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Solution Overview
Problem
Lithium secondary batteries face challenges with low energy density due to graphite's low theoretical capacity and the Si-based material's large volume expansion, which affects battery life, and the SiOx material's low initial coulombic efficiency and stability issues during electrode production.
Innovation Solution
A method involving metal doping of silicon-based materials followed by acid gas treatment to remove residual lithium, using a heat treatment process and acid gas treatment in a controlled atmosphere to enhance the silicon-based negative electrode active material's capacity and efficiency while minimizing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Si-based material is used to increase theoretical capacity, then energy density is improved, but volume expansion during charge-discharge deteriorates battery life
Solution Approach 1:
The patent uses SiOx material as a composite negative electrode active material that combines the high capacity characteristics of silicon with the structural stability of oxide compounds. This composite structure allows the material to achieve high theoretical capacity while maintaining volume stability during lithium insertion/extraction cycles, thereby improving both energy density and battery life
2Reliability
If SiOx material is used to reduce volume expansion, then battery life is improved, but initial coulombic efficiency decreases due to irreversible phase formation
Solution Approach 1:
The patent applies preliminary lithium doping to the SiOx material before electrode fabrication. This pre-introduction of lithium compensates for the lithium that will be irreversibly consumed during initial formation cycles, thereby maintaining high initial coulombic efficiency while preserving the volume stability benefits of SiOx material
3Quantity of substance
If prelithiation is applied to improve initial efficiency, then initial coulombic efficiency is improved, but residual lithium increases pH causing binder deterioration
Solution Approach 1:
The patent carefully controls the amount of lithium doping parameter within an optimal range (0.1-5.0 wt%) to achieve the desired initial coulombic efficiency while keeping residual lithium content below thresholds that would cause pH increase and binder deterioration. This parameter optimization allows simultaneous achievement of high initial efficiency and ease of manufacture
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
This approach effectively removes residual lithium, improving the battery's initial efficiency and capacity while maintaining the material's stability, leading to enhanced performance and prolonged battery life.
Implementation Method 1
the Si-based material as such has a disadvantage of deteriorated battery life characteristics due to large volume expansion ( ̃400%) in a repeated charge and discharge process
Implementation Method 2
b) an acid gas treatment process of treating the metal-doped silicon-based material in an acid gas atmosphere to remove residual metal
Implementation Method 3
a) a metal doping process of mixing a silicon-based material and a metal precursor and performing a heat treatment to dope the silicon-based material with a metal
Data Source
AI summary
Provided are a lithium-doped silicon-based negative electrode active material, a method of producing the same, and a negative electrode and a lithium secondary battery including the same. According to an exemplary embodiment of the present invention, a method of producing a negative electrode active material for a secondary battery including: a) a metal doping process of mixing a silicon-based material and a metal precursor and performing a heat treatment to dope the silicon-based material with a metal; and b) an acid gas treatment process of treating the metal-doped silicon-based material in an acid gas atmosphere to remove residual metal may be provided.