Nonaqueous Battery Electrode Coating for Gas Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium titanate-based lithium ion secondary batteries exhibit high gas generation due to side reactions with the nonaqueous electrolyte, which reduces their performance and efficiency, and previous attempts to mitigate this, such as using polymeric coatings, compromise Li ion conductivity.
Innovation Solution
Employing a fluorine-containing coating on both the positive and negative electrodes, specifically controlling the ratios of fluorine coverage to active material through X-Ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS), to suppress electrolyte decomposition while maintaining Li ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium titanate is used as negative electrode active material, then low-temperature input/output and life performance are improved, but gas generation increases due to side reactions with nonaqueous electrolyte
Solution Approach 1:
A fluorine-containing coating layer is introduced as an intermediary between the lithium titanate negative electrode and the nonaqueous electrolyte. This coating layer suppresses direct contact and side reactions between the electrolyte and lithium titanate surface, thereby reducing gas generation while maintaining lithium ion conductivity for excellent low-temperature performance and long cycle life.
Solution Approach 2:
A thin fluorine-containing coating layer is applied to the negative electrode surface. This thin film structure provides sufficient protection against electrolyte decomposition and gas generation while maintaining adequate lithium ion conductivity. The coating layer acts as a flexible barrier that prevents harmful side reactions without completely blocking ion transport.
2Object-generated harmful factors
If polymeric coating is applied to reduce gas generation, then gas generation is suppressed, but Li ion conductivity deteriorates
Solution Approach 1:
The coating material is changed from polymeric to fluorine-containing compound with specific chemical properties. The fluorine-containing coating provides both gas suppression and maintained lithium ion conductivity by altering the chemical composition and surface properties of the coating layer, achieving a balance between protection and ion transport that polymeric materials cannot provide.
3Object-generated harmful factors
If fluorine-containing coating is applied to suppress electrolyte decomposition, then gas generation is reduced, but manufacturing complexity increases due to precise coating ratio control requirements
Solution Approach 1:
The fluorine-containing coating is applied in advance during battery manufacturing before electrolyte filling. By establishing the protective coating layer beforehand, the system prevents electrolyte decomposition and gas generation from the outset. The coating application is integrated into the manufacturing process, allowing for controlled deposition without requiring post-assembly adjustments.
Solution Approach 2:
The coating is applied as a thin film with controlled thickness and composition. By optimizing the coating parameters (thickness, fluorine content, uniformity), the invention achieves effective gas suppression while maintaining manufacturing feasibility. The precise control of coating ratios ensures sufficient protection without excessive complexity in the manufacturing process.
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 fluorine-containing coatings effectively reduce gas generation at the electrodes, balancing reductive and oxidative reactions, thereby preserving the battery's input/output performance and maintaining low internal resistance.
Implementation Method 1
the fluorine-containing coatings effectively reduce gas generation at the electrodes, balancing reductive and oxidative reactions
Implementation Method 2
specifically controlling the ratios of fluorine coverage to active material through X-Ray photoelectron spectroscopy (XPS)
Implementation Method 3
time-of-flight secondary ion mass spectrometry (TOF-SIMS)
Data Source
AI summary
According to one embodiment, provided is a nonaqueous electrolyte battery including a positive electrode containing a lithium-containing nickel-cobalt-manganese oxide, a negative electrode containing a lithium titanium-containing oxide, and a nonaqueous electrolyte. A ratio PLi—F/PNi of a peak intensity PLi—F of a highest intensity peak within 682 eV to 685 eV to a peak intensity PNi of a highest intensity peak within 850 eV to 858 eV in an X-Ray photoelectron spectrum of a positive electrode surface is 0.6 or more and 1 or less. A ratio NLi—F/NTi of a peak intensity NLi—F of a highest intensity peak within 682 eV to 685 eV to a peak intensity NTi of a highest intensity peak within 454 eV to 460 eV in an X-Ray photoelectron spectrum of a negative electrode surface is 1.8 or more and 3 or less.