Phthalocyanine Electrolyte Additives for Stable Cathode CEI
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Solution Overview
Problem
Metal ions from electrode materials, particularly transition metals, dissolve into the electrolyte of electrochemical devices, leading to degradation of the electrode surface structure and the solid electrolyte interphase (SEI) due to the inability to form a stable cathodic electrolyte interface (CEI), thereby reducing the durability of the device.
Innovation Solution
Introduce a dihydrogen or metal phthalocyanine compound into the electrolyte, which reacts with transition metals in the cathode material to form a transition metal phthalocyanine compound, creating a beneficial cathodic electrolyte interface (CEI) that prevents metal ion migration and enhances the durability of the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal components and metal casings are used in electrochemical devices, then the device structure and conductivity are improved, but metal ions dissolve into the electrolyte causing electrode surface degradation and reducing device durability
Solution Approach 1:
The patent introduces a chelating agent as an intermediary substance that selectively binds to metal ions in the electrolyte, preventing them from migrating to and degrading the electrode surfaces. This mediator captures the harmful metal ions without interfering with the normal electrochemical reactions, thus resolving the contradiction between maintaining metal components for structural strength and preventing ion dissolution that harms durability
Solution Approach 2:
The patent converts the harmful effect of metal ion dissolution into a beneficial outcome by using the chelating agent to capture these ions and form stable complexes. The metal ions that would otherwise degrade the electrodes are now sequestered in a controlled manner, transforming the harmful dissolution process into a beneficial ion management mechanism that protects electrode integrity while maintaining device functionality
2Productivity
If transition metal ions migrate through the separator to the anode, then the electrochemical reactions continue, but the solid electrolyte interphase (SEI) on the anode surface degrades
Solution Approach 1:
The chelating agent acts as an intermediary that selectively binds to transition metal ions in the electrolyte, preventing their migration through the separator to the anode. This intermediary captures the metal ions before they can reach and degrade the SEI layer, while still allowing lithium ions to pass freely for normal electrochemical reactions to continue
Solution Approach 2:
The patent applies local quality by positioning the chelating agent specifically in the electrolyte where it can selectively interact with transition metal ions. The chelating agent creates a localized protective environment around metal ions, preventing their harmful migration to the anode while maintaining the overall electrochemical functionality of the device
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 formation of a transition metal phthalocyanine compound on the cathode surface stabilizes the CEI, preventing metal ion migration and mitigating SEI degradation, thus significantly improving the durability of electrochemical devices.
Implementation Method 1
the dihydrogen phthalocyanine compound and/or the metal phthalocyanine compound to react with the transition metal in the cathode material to form a transition metal phthalocyanine compound
Implementation Method 2
preventing transition metal ions from migrating to the anode
Implementation Method 3
the formation of a stable cathodic electrolyte interface (CEI)
Data Source
AI summary
The present invention provides a method involving with adding a metal phthalocyanine compound to a cathode material and/or electrolyte of an electrochemical device. After at least a full life cycle of the electrochemical device, the metal phthalocyanine compound is converted into a transition metal phthalocyanine compound derived from the cathode material. This process results in the formation of a beneficial cathodic electrolyte interface on the surface of the cathode material and/or the surface of the device. The formation of CEI prevents transition metal ions from migrating to the anode, which could otherwise affect the formation of the solid electrolyte interphase (SEI) on the anode surface, thereby enhancing the durability of the electrochemical device.