Amorphous Silicon Oxide Cathode Material Preparation
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Solution Overview
Problem
Conventional methods for preparing lithium secondary battery cathode materials using solid-phase reactions result in the formation of secondary phases that reduce battery performance and are costly due to the use of expensive starting materials and complex processes, particularly when crystalline silica is used, leading to inefficiencies and environmental concerns.
Innovation Solution
A method involving the preparation of amorphous silicon oxide as a starting material, which is milled with lithium and transition metal compounds, then heat-treated in an inert gas atmosphere to produce lithium transition metal silicon oxides, avoiding the use of crystalline silica and reducing secondary phase formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If crystalline silica is used as a starting material in solid-phase reaction, then the structural stability is improved, but secondary phases are formed that reduce battery performance
Solution Approach 1:
The patent changes the physical state parameter of silica from crystalline to amorphous form. This parameter change increases reactivity while maintaining structural stability during the solid-phase reaction, preventing secondary phase formation and improving battery performance.
Solution Approach 2:
The patent performs preliminary preparation of amorphous silica before the main solid-phase reaction. This preliminary action modifies the starting material to have higher reactivity, ensuring complete reaction and preventing secondary phase formation during the subsequent high-temperature treatment.
2Productivity
If high-temperature heat-treatment is applied to ensure reaction completeness, then the reaction efficiency is improved, but secondary phases are formed that plug lithium-ion migration channels
Solution Approach 1:
The patent changes the physical state of silica from crystalline to amorphous, which increases reactivity and allows the reaction to proceed more completely at the given temperature, reducing secondary phase formation while maintaining reaction efficiency.
Solution Approach 2:
The patent uses amorphous silica as a consumable starting material that reacts completely during the process. The amorphous structure acts as a temporary, highly reactive form that is consumed in the reaction, preventing the formation of stable secondary phases.
3Device complexity
If conventional solid-phase methods are used with crystalline silica, then the process simplicity is improved, but the manufacturing cost increases due to complex preprocessing and lower efficiency
Solution Approach 1:
The patent changes silica from crystalline to amorphous form, which increases reactivity and allows the use of simpler, lower-cost starting materials. This parameter change eliminates the need for complex preprocessing steps and reduces manufacturing costs while maintaining process simplicity.
4Reliability
If amorphous silicon oxide is used as a starting material, then the reactivity is improved and secondary phase formation is suppressed, but the preparation process becomes more complex
Solution Approach 1:
The patent changes the physical state of silica from crystalline to amorphous to increase reactivity. This single parameter change achieves the desired improvement in reaction performance without requiring fundamentally new preparation processes, thus limiting the increase in process complexity.
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 enhances the reactivity of the cathode material, suppresses the formation of non-reactive secondary phases, and achieves a higher theoretical capacity of 330 mAh/g, making it more economical and suitable for high-performance applications.
Implementation Method 1
milling the amorphous silicon oxide, a lithium silicon oxide and a transition metal silicon oxide at a predetermined ratio
Implementation Method 2
heat-treating the dried material in an atmosphere of inert gas, thereby preparing a lithium transition metal silicon oxide
Implementation Method 3
the mixture is calcined at a temperature of 1000° C. or higher, thereby preparing a cathode material
Data Source
AI summary
Disclose is a method for preparing a cathode material for a lithium secondary battery, the method comprising the steps of: preparing an amorphous silicon oxide; using the prepared silicon oxide as a starting material; and milling the amorphous silicon oxide, a lithium silicon oxide and a transition metal silicon oxide at a predetermined ratio, drying the milled material, and heat-treating the dried material in an atmosphere of inert gas, thereby preparing a lithium transition metal silicon oxide.