CNT-Coated Battery Electrode for Low Resistance After Heat Storage
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Solution Overview
Problem
Secondary batteries, such as lithium ion batteries, face challenges in achieving improved resistance characteristics, with existing carbon nanotube-based solutions providing only a certain level of resistance reduction and not adequately addressing increases in resistance after high-temperature storage.
Innovation Solution
The use of carbon nanotubes coated with elements of lower electronegativity than carbon, such as Ti, P, B, Si, Al, and W, integrated into the active material layer of the electrode, with specific average lengths and coating ratios, enhances electron conductivity and durability, resulting in improved resistance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive materials are used in the active material layer, then manufacturing is simple, but electron conductivity and resistance characteristics are insufficient
Solution Approach 1:
The patent introduces metal or metal oxide coatings as intermediary layers on carbon nanotubes. These intermediary materials facilitate better electron transfer between the carbon nanotubes and the active material, enhancing overall electron conductivity while the coating process remains relatively simple using conventional techniques like sputtering, CVD, or solution coating.
2Reliability
If the coating ratio of low-electronegativity elements is increased, then resistance characteristics improve, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the coating ratio parameter within a specific range (1-50 mass%, preferably 5-30 mass%) to achieve the best balance between initial resistance reduction and manufacturing ease. By defining this optimal parameter range, the patent makes it easier to control the coating process while maintaining excellent resistance characteristics.
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
This configuration achieves a significant reduction in initial resistance and suppresses the increase in resistance after high-temperature storage, leading to enhanced durability and performance of secondary batteries.
Implementation Method 1
at least a part of a surface of the carbon nanotube is coated with a material including an element with a lower electronegativity than that of carbon
Data Source
AI summary
An electrode using a carbon nanotube as a conductive material, and excellent in resistance characteristics is provided. An electrode for a secondary battery herein disclosed has a collector, and an active material layer formed on the collector. The active material layer includes an active material and a carbon nanotube. At least a part of the surface of the carbon nanotube is coated with a material including an element with a lower electronegativity than that of carbon.