Conductive Material Dispersion for Lithium Battery Negative Electrodes
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Solution Overview
Problem
Rechargeable lithium batteries face challenges in achieving high energy density and long cycle-life due to volume expansion and shrinkage of silicon-based active materials during charging and discharging, leading to electrode breakdown.
Innovation Solution
A conductive material dispersion for lithium batteries is developed, incorporating carbon nanotubes with specific particle size distribution and viscosity characteristics, which improves the conductivity and processability of the negative electrode, comprising a silicon and carbon composite active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the negative active material layer is thickly formed to improve energy density, then energy density is improved, but the electrode becomes more prone to breakdown due to volume expansion and shrinkage of silicon-based active material
Solution Approach 1:
The negative active material layer is divided into a first negative active material layer containing silicon-based active material and a second negative active material layer containing carbonaceous material. This segmentation allows the silicon-based layer to provide high capacity while the carbonaceous layer provides structural stability and prevents breakdown during volume expansion and shrinkage cycles.
Solution Approach 2:
The invention uses a composite structure combining silicon-based active material with carbonaceous material in a double-layer configuration. The carbonaceous material acts as a stable framework that accommodates the volume changes of silicon-based material, maintaining electrode integrity while enabling high energy density.
2Reliability
If carbon nanotubes are used as conductive material, then conductivity is improved, but viscosity of the dispersion increases making processing difficult
Solution Approach 1:
The invention optimizes the viscosity of the conductive material dispersion by controlling parameters such as carbon nanotube concentration, dispersion method, and dispersant selection. The viscosity is maintained within a specific range (100-10,000 cP) to ensure both adequate conductivity and ease of processing during electrode fabrication.
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 solution enhances the energy density and cycle-life characteristics of rechargeable lithium batteries by ensuring effective conductivity and mobility of ions, while preventing electrode disconnection and volume expansion.
Implementation Method 1
a conductive material dispersion for a rechargeable lithium battery including carbon nanotubes
Implementation Method 2
an electrolyte, and generates electrical energy due to an oxidation and reduction reaction when lithium ions are intercalated and deintercalated
Data Source
AI summary
Disclosed is a conductive material dispersion for a rechargeable lithium battery, a negative electrode prepared using the same, and a conductive material dispersion including carbon nanotubes, wherein the conductive material dispersion has a viscosity of about 10,000 cps or less, and wherein in a graph showing a particle size distribution of the dispersion, when A is a maximum peak intensity shown in a range of a particle size of about 0.5 µm or less and B is a maximum peak intensity shown in a range of a particle size of less than about 0.5 µm, the A and the B satisfy the relationship of Equation 1.A/B<1