Boron-Doped Carbon Anode Coating for Lithium Deposition Resistance
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Solution Overview
Problem
Lithium ion batteries face challenges with excessive electron conductivity leading to poor lithium deposition resistance when carbon materials are doped with boron, as it results in unbalanced ion and electron conduction.
Innovation Solution
A negative electrode active material is developed by incorporating a carbon material with a controlled boron content (0.2-3.5 atomic %) and coating it with a low-crystallinity carbon film, maintaining surface electron conductivity while suppressing excessive electron supply, thereby enhancing lithium deposition resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon material is doped with boron to improve electron conductivity, then electron conductivity is improved, but lithium deposition resistance deteriorates due to excessive electron supply
Solution Approach 1:
The patent changes the crystallinity parameter of the carbon material by controlling the R value (ratio of D band to G band in Raman spectrum) to be 0.35 or more and 0.85 or less. This parameter change modifies the electron conductivity to achieve a balance between electron supply and lithium ion conduction, preventing lithium deposition while maintaining necessary electron conductivity for battery operation.
Solution Approach 2:
The patent creates a composite carbon material that combines boron-doped carbon with controlled crystallinity characteristics. The composite structure integrates the electron conductivity enhancement from boron doping with the moderated electron supply effect from controlled crystallinity (R value control), achieving both improved electron conductivity and lithium deposition resistance simultaneously.
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 approach improves lithium deposition resistance and maintains electron conductivity within a predetermined range, ensuring stable battery performance.
Implementation Method 1
a carbon film that covers the carbon material
Implementation Method 2
the carbon material is doped with boron
Implementation Method 3
the content of the boron element doped such that the carbon element on the surface of the carbon material is substituted
Implementation Method 4
the R value is a ratio of a D band with respect to a G band in a Raman spectrum of the negative electrode active material
Data Source
AI summary
A negative electrode active material for a lithium ion battery, the negative electrode active material comprising a carbon material and a carbon film covering the carbon material, wherein the carbon material comprises carbon and boron, the content of boron in the carbon material is 0.2 atomic % or more and less than 3.5 atomic %, the negative electrode active material has an R value of 0.35 or more and 0.85 or less, and the R value is a ratio of a D band to a G band in a Raman spectrum of the negative electrode active material.