Composite Active Material Particle for Stable Silicon Contact
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Solution Overview
Problem
The charge-discharge efficiency of batteries using silicon as an active material is insufficient due to disconnection of electrical contact between silicon particles and lithium silicate phases during expansion and contraction, leading to reduced discharge capacity compared to charge capacity.
Innovation Solution
A composite active material particle comprising a lithium silicate phase, silicon particles dispersed within, and an electron-conductive material, such as carbon or metal, which maintains electrical contact and absorbs expansion and contraction, preventing disconnection during charge and discharge cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon particles are dispersed in lithium silicate phase to create composite active material, then capacity is improved, but electrical contact between silicon particles is disconnected during expansion and contraction, reducing charge-discharge efficiency
Solution Approach 1:
An electron-conductive material is introduced as an intermediary substance between silicon particles and lithium silicate phase. This mediator maintains electrical contact between silicon particles during charge-discharge cycles, preventing disconnection caused by expansion and contraction while preserving the high capacity benefits of silicon-lithium silicate composites.
Solution Approach 2:
The invention creates a multi-component composite material system consisting of silicon particles, lithium silicate phase, and electron-conductive material. This composite structure combines the high capacity of silicon, the stability of lithium silicate, and the electrical conductivity of the conductive material, resolving the contradiction between capacity and charge-discharge efficiency.
2Use of energy by moving object
If silicon particles expand and contract during charge and discharge cycles, then lithium occlusion and release is enabled, but electrical contact between silicon particles and lithium silicate phases is disconnected, reducing discharge capacity
Solution Approach 1:
The electron-conductive material serves as a mediator that remains in contact with silicon particles during their expansion and contraction. This intermediary ensures continuous electrical pathways for electron transfer during lithium occlusion and release, preventing the disconnection that would otherwise reduce discharge capacity.
Solution Approach 2:
The invention changes the physical and chemical parameters of the composite material by incorporating electron-conductive material with specific conductivity properties. This parameter change enables the system to maintain electrical contact during the dynamic parameter changes of silicon expansion and contraction, preserving discharge capacity while enabling lithium occlusion and release.
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 inclusion of an electron-conductive material in the composite active material particle enhances charge-discharge efficiency by maintaining electrical contact between silicon particles, thereby reducing the decrease in discharge capacity relative to charge capacity.
Implementation Method 1
an electron-conductive material dispersed in the lithium silicate phase, the electron-conductive material including a carbon material
Data Source
AI summary
A composite active material particle of the present disclosure includes a lithium silicate phase, a plurality of silicon particles dispersed in the lithium silicate phase, and an electron-conductive material dispersed in the lithium silicate phase, the electron-conductive material including a carbon material.