Silicon Oxide Anode Composition for Low-Rebound Battery Electrodes
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Solution Overview
Problem
The use of silicon as a negative electrode active material in batteries results in severe volume expansion, leading to increased thickness rebound and porosity of the negative electrode plate, which damages the conductive network and adversely affects the cycle stability and cycle-life of the battery.
Innovation Solution
A negative electrode active material comprising a combination of first and second silicon oxides with specific particle diameter ratios and distributions is used to control thickness rebound and maintain good electrical contact between particles, improving cycle stability and cycle-life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon is used as negative electrode active material to achieve high capacity, then the theoretical capacity per gram increases by more than 10 times compared to graphite, but severe volume expansion occurs during charging resulting in large thickness rebound and increased porosity of the negative electrode plate
Solution Approach 1:
The patent changes the particle size parameters of silicon oxide, specifically controlling Dn10 within 0.5-2.0 μm and Dv50 within 2.0-5.0 μm, to optimize the negative electrode plate structure and reduce volume expansion effects
Solution Approach 2:
The patent uses silicon oxide as a composite material alternative to pure silicon, combining the high capacity benefits of silicon with the structural stability of oxide materials to reduce volume expansion and maintain electrode integrity
2Volume of stationary object
If the negative electrode plate structure transforms from dense state to loose porous state due to volume expansion, then the porosity increases, but the conductive network is damaged and electrical contact between particles becomes poor
Solution Approach 1:
The patent controls the particle size distribution parameters (Dn10 and Dv50) to maintain optimal packing density and porosity balance, preventing excessive pore formation that would damage the conductive network while preserving electrical contact between particles
3Length of moving object
If the negative electrode plate has larger thickness rebound due to volume expansion, then the porosity becomes higher, but the cycle stability and cycle-life of the battery are seriously influenced
Solution Approach 1:
The patent optimizes the particle size parameters (Dn10: 0.5-2.0 μm, Dv50: 2.0-5.0 μm) to control thickness rebound within acceptable limits, thereby maintaining structural integrity over multiple charge-discharge cycles and improving cycle-life and cycle stability
Data Source
AI summary
The present disclosure provides a negative electrode active material, a battery and a device. The negative electrode active material comprises a first silicon oxide and a second silicon oxide, wherein, a ratio of a particle diameter Dn10 of the first silicon oxide to a particle diameter Dn10 of the second silicon oxide is 8˜25, the particle diameter Dn10 of the first silicon oxide is 1.0 μm˜5.0 μm, the particle diameter Dn10 of the second silicon oxide is 0.05 μm˜0.50 μm. By selecting two kinds of silicon oxides with specific ranges of Dn10 to match with each other, the present disclosure controls the thickness rebound of negative electrode plate, ensures good electrical contact between the negative electrode active material particles, in turn is beneficial to improve the cycle stability and the cycle-life of the battery.