Silicon-Graphite Anode Composition for Better Slurry Dispersion
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Solution Overview
Problem
Existing lithium-ion batteries face issues with poor cycle performance and dispersibility of negative electrode materials, particularly with silicon-based materials, leading to problems like particle agglomeration and bubble formation during production, which affect the battery's service life and efficiency.
Innovation Solution
A negative electrode plate comprising graphite and silicon-based materials, combined with a conductive binder containing carbon nanotubes and a dispersing agent like lignosulfonate or humic acid, to enhance dispersion and conductivity, thereby improving the electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon nanotubes are added to the slurry to improve cycle performance of silicon-based materials, then capacity retention is improved, but dispersion quality deteriorates and production cost increases
Solution Approach 1:
The patent introduces a specific binder formulation containing carboxymethyl cellulose and styrene-butadiene rubber as intermediary substances that mediate between the carbon nanotubes and silicon-based materials. This binder system improves the dispersion of carbon nanotubes while maintaining their effectiveness in enhancing cycle performance, thereby resolving the contradiction between reliability improvement and composition stability.
2Ease of manufacture
If water-based negative electrode slurry is used for production, then manufacturing cost is reduced, but bubble formation occurs leading to exposed foil and particle aggregation
Solution Approach 1:
The patent uses carboxymethyl cellulose and styrene-butadiene rubber in the binder as intermediary substances that suppress bubble formation in water-based slurry. These additives act as surfactants and stabilizers that prevent gas entrapment and foam formation during the coating process, eliminating the harmful effects while maintaining the cost advantages of water-based systems.
3Quantity of substance
If amorphous silicon monoxide is used as negative electrode material, then energy density is improved, but cycle performance deteriorates
Solution Approach 1:
The patent creates a composite material system where amorphous silicon monoxide particles are combined with graphite and carbon nanotubes in a specific formulation. The carbon nanotubes form a conductive network that maintains electrical conductivity during cycling, while the binder system provides mechanical stability. This composite approach allows the high capacity of silicon monoxide to be utilized while the carbon matrix accommodates volume changes and maintains cycle performance.
4Stability of the object's composition
If carbon nanotubes are added to improve dispersibility of electrode slurry, then slurry homogeneity is improved, but production cost increases and equipment complexity increases
Solution Approach 1:
The patent employs carboxymethyl cellulose and styrene-butadiene rubber as intermediary dispersants that facilitate carbon nanotube dispersion in the slurry without requiring specialized mixing equipment. These binder additives provide steric and electrostatic stabilization that prevents nanotube aggregation, achieving homogeneous slurry with conventional coating equipment and without additional processing steps.
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 results in improved slurry dispersibility, increased initial discharge capacity, enhanced initial efficiency, and better capacity retention after cycling, while reducing particle agglomeration and bubble formation.
Implementation Method 1
a binder including carbon nanotubes
Implementation Method 2
a dispersing agent including one or two of lignosulfonate and humic acid
Data Source
AI summary
A negative electrode plate for a lithium battery and a lithium-ion secondary battery including same are provided. The negative electrode plate includes a negative electrode current collector and a negative electrode material. The negative electrode material includes: a negative electrode active material including graphite and a silicon-based material; a conductive agent; a binder including carbon nanotubes; and a dispersing agent including one or both of lignosulfonate and humic acid.