Battery Electrode Paste Using Treated CNTs for Low Resistance
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Solution Overview
Problem
Conventional secondary battery pastes struggle to reduce internal resistance while maintaining excellent cycle characteristics.
Innovation Solution
A paste for secondary batteries incorporating surface-treated carbon nanotubes with specific surface properties, a polymer with nitrile and conjugated diene monomer units, and a hydrophilic group, which form a slurry that reduces internal resistance and enhances cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive additives and polymer dispersants are used in paste formulation, then the paste can be easily manufactured and applied, but the internal resistance of the secondary battery remains high and cycle characteristics are insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the surface base content (0.01-0.10 mmol/g) and surface acid content ratio (0.1-1.0) of carbon nanotubes, as well as the polymer composition ratios (nitrile group-containing monomer unit 10-40 mass%, conjugated diene monomer unit 15-55 mass%). These specific parameter ranges optimize both the electrical conductivity and cycle stability of the battery while maintaining manufacturability through controlled chemical modifications of the carbon nanotube surface and standardized polymer synthesis procedures.
Solution Approach 2:
The patent employs composite materials by combining surface-treated carbon nanotubes with a specifically formulated polymer system. The carbon nanotubes undergo surface treatment to introduce base groups (amines, amides, or carbonyls) that interact with the polymer matrix containing nitrile groups and conjugated diene units. This composite structure creates synergistic effects where the treated carbon nanotubes provide enhanced conductivity pathways while the polymer matrix ensures stable adhesion and electrochemical performance, thereby improving cycle characteristics without significantly complicating the manufacturing process.
2Reliability
If surface treatment of carbon nanotubes is optimized to reduce internal resistance, then battery performance improves, but the manufacturing process becomes more complex
Solution Approach 1:
The patent reduces device complexity by establishing specific parameter ranges for surface treatment that balance performance improvement with process simplicity. The surface base content is controlled at 0.01-0.10 mmol/g and the surface acid content ratio is maintained at 0.1-1.0, which can be achieved through standardized acid-base treatment protocols. These parameter specifications provide clear manufacturing targets that simplify process control while delivering optimal internal resistance reduction and cycle stability.
Solution Approach 2:
The patent uses the polymer dispersant as an intermediary that facilitates the integration of surface-treated carbon nanotubes into the electrode slurry. The polymer, containing nitrile group-containing monomer units (10-40 mass%) and conjugated diene monomer units (15-55 mass%), acts as a mediator that interacts with the base groups on the carbon nanotube surface through hydrogen bonding or dipole interactions. This intermediary role of the polymer simplifies the overall manufacturing process by enabling direct mixing of treated carbon nanotubes with the slurry components without requiring additional surface modification steps, thereby reducing process complexity while maintaining effective conductivity enhancement.
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 effectively decreases internal resistance and improves cycle characteristics of secondary batteries by optimizing the surface treatment of carbon nanotubes and the composition of the polymer, leading to improved electrode stability and conductivity.
Implementation Method 1
the conductive additive includes one or more surface-treated carbon nanotubes having a surface base content of not less than 0.01 mmol/g and not more than 0.10 mmol/g and a ratio of surface acid content relative to the surface base content of not less than 0.1 and not more than 1.0
Implementation Method 2
a polymer, and a dispersion medium, wherein the conductive additive includes one or more surface-treated carbon nanotubes
Data Source
AI summary
Provided are a paste for a secondary battery, and method of producing the same, with which it is possible to produce an electrode that can reduce internal resistance of a secondary battery and that can cause the secondary battery to display excellent cycle characteristics. The paste for a secondary battery contains a conductive additive, a polymer, and a dispersion medium. The conductive additive includes one or more carbon nanotubes having a surface base content of not less than 0.01 mmol/g and not more than 0.10 mmol/g and a ratio of surface acid content relative to the surface base content of not less than 0.1 and not more than 1.0.