Silane-Coated Niobium-Titanium Oxide for Stable Li-Ion Anodes
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Solution Overview
Problem
Niobium-titanium-based oxide active materials in lithium ion secondary batteries face issues with insufficient surface coverage by silane coupling agents, leading to State Of Charge (SOC) shifts, metal elution, and decreased discharge capacity due to high reactivity with electrolytes and moisture retention.
Innovation Solution
The surface of niobium-titanium-based oxide particles is treated with a base to increase the density of hydroxyl groups, followed by a silane coupling agent application to enhance hydrophobic coverage, achieving a peak area ratio of Si2p to Nb3d peaks between 0.40 and 1.0 as measured by X-ray photoelectron spectroscopy, thereby reducing moisture content and improving cycle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the surface of niobium-titanium-based oxide is treated with a silane coupling agent to improve hydrophobic coverage, then moisture resistance should increase, but the coverage on the surface is insufficient due to the specific properties of niobium-titanium-based oxide
Solution Approach 1:
The patent changes the chemical parameters of the silane coupling agent by selecting specific types (alkyl-based silane coupling agents such as methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, or butyltrimethoxysilane) and adjusting the treatment conditions to achieve optimal coverage on niobium-titanium-based oxide surfaces, resolving the insufficient coverage issue while maintaining moisture resistance
Solution Approach 2:
The silane coupling agent acts as an intermediary substance that forms a bridge between the hydrophilic niobium-titanium-based oxide surface and the hydrophobic requirements, creating a hydrophobic layer that prevents moisture contact while ensuring adequate surface coverage through proper selection and treatment
2Reliability
If the active material surface is treated with silane coupling agent to prevent SOC shift and metal elution, then battery reliability should improve, but overcoating may occur causing conductivity losses
Solution Approach 1:
The patent applies partial action by controlling the silane coupling agent treatment to achieve just the right amount of coverage - sufficient to prevent SOC shift and metal elution but not excessive to cause conductivity loss. The treatment is optimized to cover only the necessary surface area of the active material
Solution Approach 2:
The patent uses X-ray photoelectron spectroscopy (XPS) to measure the Si2p peak area ratio and provides feedback control by adjusting the treatment conditions to maintain the ratio within the optimal range of 0.40≤A≤1.00, ensuring adequate protection without overcoating that would harm conductivity
3Manufacturing precision
If base treatment is applied to increase hydroxyl group density before silane coupling, then surface coverage should improve, but additional processing steps increase manufacturing complexity
Solution Approach 1:
The patent applies preliminary action by performing base treatment before silane coupling agent application to increase hydroxyl group density on the niobium-titanium-based oxide surface. This preliminary step prepares the surface for better silane coupling, ensuring adequate coverage and hydrophobic protection
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 approach effectively suppresses SOC shifts and maintains coulombic efficiency, preventing overcoating and conductivity losses, resulting in improved cycle characteristics and discharge capacity of secondary batteries.
Implementation Method 1
The surface of niobium-titanium-based oxide particles is treated with a base to increase the density of hydroxyl groups
Implementation Method 2
followed by a silane coupling agent application to enhance hydrophobic coverage
Implementation Method 3
enhance hydrophobic coverage, achieving a peak area ratio of Si2p to Nb3d peaks between 0.40 and 1.0
Implementation Method 4
as measured by X-ray photoelectron spectroscopy
Data Source
AI summary
A niobium-titanium-based oxide includes niobium-titanium-based oxide particles, wherein an Si2p peak area and an Nb3d peak area, as measured by X-ray photoelectron spectroscopy for the niobium-titanium-based oxide particles, satisfy a ratio A of 0.40≤A≤1.0, provided that the ratio A is the Si2p peak area/the Nb3d peak area.