Silicon Composite Anode Material via Photothermal Silica Reduction
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Solution Overview
Problem
Carbon-based negative electrode active materials for lithium secondary batteries have a low theoretical capacity, while silicon-based materials offer higher capacity but require lengthy high-temperature heat treatment, which is inefficient and costly.
Innovation Solution
A method involving the use of a silica precursor with an organic functional group and a carbon layer, subjected to heat-treatment followed by photo-processing, to produce a silicon composite with enhanced capacity, utilizing rapid photothermal treatment to reduce silica and silicon oxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high-temperature heat treatment is used to reduce silica, then silicon-based negative electrode active material is obtained, but the treatment time is long and energy consumption is high
Solution Approach 1:
The patent replaces the conventional thermal reduction process with a photochemical reduction process using visible light. The silica precursor with organic functional groups undergoes photochemical reaction under visible light irradiation to directly produce silicon-based negative electrode active material, eliminating the need for lengthy high-temperature heat treatment and significantly reducing energy consumption and treatment time
Solution Approach 2:
The patent introduces organic functional groups (such as vinyl groups, thiol groups, or phenyl groups) onto the silica precursor surface, which fundamentally changes the chemical properties of the material. These organic functional groups enable the silica to undergo photochemical reduction instead of thermal reduction, allowing the reduction process to proceed under mild visible light conditions rather than requiring high-temperature heat treatment
2Reliability
If carbon-based negative electrode active materials are used, then stable electrochemical reactivity is achieved, but the theoretical capacity is low
Solution Approach 1:
The patent creates a composite material by grafting organic functional groups onto the silica precursor surface. This composite structure combines the stability of silica with the high capacity characteristics of silicon, enabling the material to exhibit both stable electrochemical reactivity and high theoretical capacity (950-4200 mAh/g), thus resolving the contradiction between stability and capacity
3Reliability
If silica is reduced by heat treatment in hydrogen atmosphere, then silicon is obtained, but the process is costly and time-consuming
Solution Approach 1:
The patent substitutes the conventional thermal reduction process in hydrogen atmosphere with a photochemical reduction process using visible light. The organic functional groups on the silica precursor act as reducing agents under light irradiation, directly converting silica to silicon-based materials without requiring hydrogen gas or high-temperature heat treatment, thereby dramatically improving production efficiency and reducing costs
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 results in a negative electrode active material with an initial capacity of 950 mAh/g to 4,200 mAh/g, significantly higher than carbon-based materials, and supports fast charge/discharge speeds with improved structural stability and conductivity.
Implementation Method 1
a means for improving a light absorption rate for efficient light treatment is introduced
Implementation Method 2
subjected to heat-treatment followed by photo-processing, to produce a silicon composite with enhanced capacity, utilizing rapid photothermal treatment to reduce silica and silicon oxide
Implementation Method 3
heat-treating the negative electrode active material precursor to manufacture a negative electrode active material intermediate including a first silicon composite
Data Source
AI summary
Disclosed are a negative electrode active material for secondary batteries and a method of manufacturing the same. The method of manufacturing the negative electrode active material for secondary batteries of the present disclosure includes manufacturing a negative electrode active material precursor, the negative electrode active material precursor including a silica precursor including an organic functional group; and a carbon layer surrounding a surface of the silica precursor including the organic functional group; heat-treating the negative electrode active material precursor to manufacture a negative electrode active material intermediate including a first silicon composite; and photo-processing the negative electrode active material intermediate to manufacture a negative electrode active material including a second silicon composite. The negative electrode active material for secondary batteries according to an embodiment of the present disclosure can implement high capacity characteristics.