Boron-Doped Graphite Anode Mixture for Silicon Capacity Retention
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Solution Overview
Problem
Existing non-aqueous electrolyte lithium secondary batteries have room for improvement in capacity retention rate.
Innovation Solution
An anode mixture containing a plurality of carbon particles and a plurality of silicon-based particles, where the carbon particles include boron-doped scaly graphite particles, and the content of silicon-based particles relative to carbon particles is between 5 mass % to 60 mass %, and the content of scaly graphite particles relative to carbon particles is 1.5 mass % or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based particles are added to increase battery capacity, then the battery capacity increases, but the capacity retention rate deteriorates
Solution Approach 1:
Boron-doped scaly graphite particles are introduced as an intermediary material between silicon-based particles and the electrolyte. This intermediary forms a stable conductive network that mediates the interaction between silicon particles and electrolyte, preventing direct harmful reactions while maintaining capacity. The boron-doped graphite acts as a buffer that preserves capacity retention while allowing silicon to contribute to high capacity.
Solution Approach 2:
The patent creates a composite anode material system combining silicon-based particles with boron-doped scaly graphite particles. This composite structure leverages the high capacity of silicon while the boron-doped graphite provides structural stability and conductive pathways, achieving both high capacity and good capacity retention through material composition synergy.
2Quantity of substance
If silicon-based particles are added to increase battery capacity, then the battery capacity increases, but the electronic conductivity deteriorates
Solution Approach 1:
Boron-doped scaly graphite particles serve as a conductive intermediary network that bridges silicon-based particles. The boron doping enhances the electronic conductivity of the graphite, creating efficient electron transport pathways that mediate between the low-conductivity silicon particles and the external circuit, thus maintaining overall electronic conductivity while enabling high capacity.
Solution Approach 2:
The patent changes the chemical composition parameter by doping graphite with boron, which fundamentally alters the electronic structure and enhances electrical conductivity. This parameter change in the graphite material (through boron substitution) creates a conductive matrix that compensates for the poor conductivity of silicon-based particles.
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 anode mixture significantly improves the capacity retention rate of lithium secondary batteries by enhancing electronic conductivity and forming efficient conductive paths for silicon-based particles.
Implementation Method 1
The carbon particles (A) include a plurality of boron-doped scaly graphite particles (A1)... a boron doping content in the scaly graphite particles (A1) may be 0.2 atm % or more
Data Source
AI summary
An anode mixture contains a plurality of carbon particles and a plurality of Si-based particles. The plurality of carbon particles includes a plurality of scaly graphite particles doped with boron. The content of the plurality of Si-based particles relative to the plurality of carbon particles is 5 mass % to 60 mass %. The content of the plurality of scaly graphite particles relative to the plurality of carbon particles is 1.5 mass % or more.