Silane-Modified Lithium-Ion Electrolyte for High-Nickel Cathode Stability
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Solution Overview
Problem
Current lithium ion battery electrolytes fail to effectively improve the interface stability and cycle life of high-nickel and high-voltage positive electrode materials, leading to reduced battery performance and short cycle life due to increased oxidability and metal ion dissolution.
Innovation Solution
A lithium ion electrolyte composition including an ester solvent, a lithium salt, and specific electrolyte additives such as p-aminophenyl trimethoxysilane, 3-aminopropyl trimethoxysilane, and other silane coupling agents, which form a stable interface with high-nickel positive electrode materials, inhibiting oxygenolysis and metal ion dissolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-nickel and high-voltage positive electrode materials are used to improve energy density, then energy density is improved, but interface stability deteriorates and metal ion dissolution increases
Solution Approach 1:
The patent introduces silane coupling agents (such as γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane) as intermediary substances that form a protective interface layer between the high-nickel positive electrode material and the electrolyte. This intermediary layer acts as a barrier that prevents direct contact and harmful reactions, thereby maintaining interface stability while allowing the high-nickel material to function at high energy density
Solution Approach 2:
The patent creates a composite structure by combining the high-nickel positive electrode material with silane coupling agents that form a coating layer. This composite material approach allows the beneficial high energy density properties of high-nickel materials to be retained while the silane-based coating provides protective functions that prevent metal ion dissolution and maintain interface stability
2Use of energy by moving object
If high-nickel and high-voltage positive electrode materials are used to improve energy density, then energy density is improved, but cycle life deteriorates
Solution Approach 1:
The patent applies silane coupling agents as electrolyte additives that perform preliminary protective action by forming a stable interface coating on the positive electrode material before battery operation begins. This preliminary coating prevents subsequent degradation reactions during cycling, thereby extending cycle life while maintaining the high energy density capability of the high-nickel material
Solution Approach 2:
The silane coupling agents serve as intermediary substances that form a protective barrier between the high-nickel positive electrode material and the electrolyte. This intermediary layer prevents harmful interactions during cycling, reducing metal ion dissolution and maintaining interface stability over extended periods, thus improving cycle life
3Reliability
If conventional electrolyte additives are used, then basic electrolyte function is maintained, but ion mobility is not improved and film forming impedance is not reduced
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by introducing silane coupling agents with specific functional groups (methacryloxy, glycidoxy) that can participate in film formation reactions. These parameter changes in electrolyte composition enable the formation of low-impedance SEI films that facilitate improved ion mobility while maintaining basic electrolyte functions
Solution Approach 2:
The patent creates a composite electrolyte system by combining conventional electrolyte components with silane coupling agents. This composite electrolyte formulation works synergistically to maintain basic electrolyte functions while the silane components specifically address ion mobility and film forming impedance through their unique chemical properties
4Reliability
If conventional electrolyte additives are used, then basic electrolyte function is maintained, but metal ion dissolution is not effectively inhibited
Solution Approach 1:
The silane coupling agents act as intermediary substances that form a protective coating layer on the positive electrode material surface. This intermediary layer physically separates the electrolyte from the metal ions, preventing their dissolution into the electrolyte while still allowing the electrolyte to perform its basic ionic conduction function
Solution Approach 2:
The patent converts the potential harm of high-nickel material reactivity into a benefit by using silane coupling agents that preferentially react with the electrode surface to form a protective layer. This layer transforms the harmful high reactivity of high-nickel materials into a beneficial stable interface that prevents metal ion dissolution
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 proposed electrolyte significantly enhances the interface stability and cycle life of lithium ion batteries and capacitors, with capacity retention exceeding 80% after 1000 cycles for batteries and energy retention exceeding 90% after 20,000 cycles for capacitors.
Implementation Method 1
By forming an inert layer on the surface of a positive electrode, the continuous oxygenolysis of the electrolyte on the surface of the positive electrode material can be inhibited
Implementation Method 2
the dissolution of metal ions can be reduced
Data Source
AI summary
A lithium ion electrolyte, a preparation method and application thereof are provided. The lithium ion electrolyte includes: an ester solvent, a lithium salt and an electrolyte additive, where the electrolyte additive includes a compound as shown in the following formula I. According to the electrolyte provided by the present disclosure, all components have a synergistic effect and are matched with one another, so that the electrolyte can improve the interface stability of a high-nickel positive electrode material and prolong the cycle life of a lithium ion battery and a lithium ion capacitor.