Silicon Oxide Anode Material for Lithium Battery
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Solution Overview
Problem
Lithium secondary batteries using non-carbon based anode active materials face challenges in maintaining charge and discharge efficiency and lifetime due to dendrite formation and structural changes during lithium ion intercalation, leading to insufficient retention of discharge capacity and initial efficiency.
Innovation Solution
A method of manufacturing silicon oxide by mixing silicon and silicon dioxide in a reaction chamber, achieving a high vacuum and reacting them in a reducing atmosphere between 1300°C to 1500°C, allowing control of oxygen content and maintaining the SiOx structure, which enhances the reaction with lithium ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If non-carbon based anode active materials (silicon, tin, germanium, zinc, lead) are used to increase energy density and charge-discharge capacity, then the theoretical capacity is improved, but dendrites or non-conductive compounds are generated during repeated charge-discharge, causing charge-discharge characteristics to degrade and expansion-shrinkage to increase, resulting in insufficient lifetime characteristics and initial efficiency
Solution Approach 1:
The patent uses composite materials by combining silicon with silicon dioxide to form silicon oxide (SiOx). This composite structure leverages the high capacity of silicon while the silicon dioxide component provides structural stability and prevents dendrite formation. The resulting material maintains high charge-discharge capacity while significantly improving lifetime characteristics and initial efficiency by eliminating the harmful effects of pure silicon's expansion-shrinkage cycles.
Solution Approach 2:
The patent applies parameter changes by precisely controlling the oxygen content in silicon oxide through specific reaction conditions (temperature of 1400-1600°C, pressure of 20 Pa or less, and controlled oxygen flow). By adjusting these parameters, the silicon oxide product achieves optimal properties with reduced expansion-shrinkage and improved structural stability during lithium ion intercalation, thereby enhancing both capacity and reliability.
2Quantity of substance
If non-carbon based anode active materials are used to improve charge-discharge capacity, then energy density is increased, but expansion and shrinkage increase during lithium ion intercalation and deintercalation, leading to insufficient initial efficiency
Solution Approach 1:
The patent creates a composite material system where silicon provides high energy density through its superior theoretical capacity, while silicon dioxide contributes structural stability during lithium ion intercalation and deintercalation. This composite approach maintains the high energy density benefits while dramatically improving initial efficiency by reducing expansion-shrinkage volume changes that would otherwise degrade performance.
3Productivity
If silicon and silicon dioxide are reacted at high temperature to produce silicon oxide, then the reaction proceeds efficiently, but without high vacuum conditions, the oxygen content cannot be precisely controlled, affecting the initial efficiency and lifetime characteristics of the battery
Solution Approach 1:
The patent employs a high vacuum environment (20 Pa or less) during the reaction of silicon and silicon dioxide. This inert atmosphere prevents unwanted oxidation and allows precise control of oxygen content by introducing controlled amounts of oxygen gas. The vacuum condition enables efficient high-temperature reaction while simultaneously providing the manufacturing precision needed to achieve the target oxygen content range (0.8 ≤ x ≤ 1.2 in SiOx), thereby optimizing both productivity and manufacturing precision.
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 method increases the initial efficiency of secondary batteries and improves lifetime characteristics by controlling the oxygen content in silicon oxide, maintaining the structure during reactions with lithium, thus enhancing the battery's performance.
Implementation Method 1
reacting the mixture of silicon and silicon dioxide in a reducing atmosphere, wherein the reaction temperature is in a range of 1300°C to 1500°C
Implementation Method 2
depressurizing a pressure of the reaction chamber to obtain a high degree of vacuum
Data Source
Figure 1(a)~1(b)
AI summary
Provided is a method of manufacturing silicon oxide by which an amount of oxygen of the silicon oxide may be controlled. The method of manufacturing silicon oxide may include mixing silicon and silicon dioxide to be included in a reaction chamber, depressurizing a pressure of the reaction chamber to obtain a high degree of vacuum while increasing a temperature in the reaction chamber to a reaction temperature, and reacting the mixture of silicon and silicon dioxide in a reducing atmosphere.