Silicon Active Material for All Solid State Battery Volume Variation
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Solution Overview
Problem
The large volume variation of silicon (Si) during charge/discharge in all solid state batteries leads to adverse effects such as energy density decrease and increased confining jig size, making it difficult to improve energy density while limiting the use of Si particles.
Innovation Solution
An active material comprising Si with specific infrared peak intensity ratios (I1/I2) and including silicon clathrate II, I, or diamond type crystal phases, and voids within primary particles, which suppresses volume variation by improving surface polarity and dispersion in the electrode layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Si based active material is used to achieve high energy density, then the theoretical capacity is large and useful for high energy condensation, but the volume variation of electrode layer is large during charge/discharge
Solution Approach 1:
The patent applies local quality by creating a composite structure where Si nanoparticles are embedded in a silicon oxide skeleton. The Si regions provide high capacity while the silicon oxide matrix provides structural stability and accommodates volume changes locally, allowing each part to have different functions that resolve the contradiction between high capacity and volume stability
Solution Approach 2:
The patent uses composite materials by combining Si nanoparticles with silicon oxide to form a hybrid structure. This composite approach allows the material to simultaneously exhibit the high capacity of Si and the volume stability of silicon oxide, directly resolving the technical contradiction between theoretical capacity and volume variation during charge/discharge cycles
2Quantity of substance
If Si particles are used to achieve high energy density, then the theoretical capacity is large, but the confining jig size increases and energy density decreases
Solution Approach 1:
The patent applies local quality by creating a composite structure where Si nanoparticles are embedded in a silicon oxide skeleton. The Si regions provide high capacity while the silicon oxide matrix provides structural stability and accommodates volume changes locally, allowing each part to have different functions that resolve the contradiction between high capacity and volume stability
Solution Approach 2:
The patent uses composite materials by combining Si nanoparticles with silicon oxide to form a hybrid structure. This composite approach allows the material to simultaneously exhibit the high capacity of Si and the volume stability of silicon oxide, directly resolving the technical contradiction between theoretical capacity and volume variation during charge/discharge cycles
Data Source
AI summary
A main object of the present disclosure is to provide an active material wherein the volume variation of an electrode layer during charge/discharge may be suppressed. The present disclosure achieves the object by providing an active material used for an all solid state battery, the active material comprising at least Si, and in infrared spectrum, when a maximum peak intensity in 900 cm−1 or more and 950 cm−1 or less is regarded as I1, and a maximum peak intensity in 1000 cm−1 or more and 1100 cm−1 or less is regarded as I2, the I1 and the I2 satisfy 0.55≤I2/I1≤1.0, and 0.01≤I1.