Lithium-Ion Battery Electrolyte Additive for Mn Dissolution Control
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Solution Overview
Problem
Manganese dissolution from the positive electrode in lithium ion batteries leads to decreased lithium storage capacity and poor cycle and storage performance, especially at high temperatures, due to ion exchange with lithium at the negative electrode.
Innovation Solution
A lithium ion battery design incorporating a lithium manganese-based positive electrode active material, a non-aqueous electrolyte with a specific additive, and a separator with controlled porosity, capacitance, and mass content of the additive, forming a compact interface film to inhibit manganese ion transfer and enhance safety and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a positive active material containing manganese is adopted to enhance safety performance, then safety performance is improved, but manganese ions dissolve in the electrolyte and transfer to the negative electrode, occupying lithium intercalation positions and decreasing lithium storage capacity
Solution Approach 1:
The patent introduces a coating layer on the positive electrode material surface that acts as an intermediary barrier. This coating layer prevents direct contact between manganese ions and the electrolyte, thereby blocking the dissolution and migration of manganese ions to the negative electrode while allowing lithium ions to pass through, thus resolving the contradiction between safety performance and lithium storage capacity
Solution Approach 2:
The patent modifies the surface properties of the positive electrode material by applying a coating layer with specific chemical composition and structural characteristics. This parameter change creates a protective interface that selectively allows lithium ion transport while blocking manganese ion dissolution, thereby maintaining both safety performance and lithium storage capacity
2Reliability
If manganese-containing positive electrode material is used, then safety performance is improved, but ion exchange between manganese and lithium at the negative electrode occurs, resulting in capacity loss and poor cycle and storage performances
Solution Approach 1:
The coating layer serves as a protective intermediary that prevents manganese ions from reaching the negative electrode. By blocking the ion exchange process between manganese and lithium at the negative electrode, the coating layer preserves lithium intercalation sites and maintains battery capacity over extended cycling and storage periods, thereby improving cycle and storage performances while retaining safety benefits
Solution Approach 2:
The patent applies a protective coating layer to the positive electrode material before battery assembly and operation. This preliminary protective action prevents manganese ion dissolution and migration from occurring, thereby preserving battery capacity and performance throughout the operational life and storage period
3Reliability
If the concentration of additive is increased to inhibit manganese dissolution, then manganese ion transfer is reduced, but the relationship between porosity, additive content, and capacitance must be precisely controlled to maintain optimal performance
Solution Approach 1:
The patent establishes specific quantitative relationships between separator porosity (q), additive mass content (m), and positive electrode capacitance per unit area (P), defining an optimal range for the product q×m/P. By controlling these parameters within specified ranges, the patent achieves effective manganese dissolution inhibition while maintaining balanced battery performance, thus managing the complexity through defined parameter windows rather than uncontrolled optimization
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 design prevents manganese ion dissolution, stabilizes the negative electrode, and improves safety and cycle performance while maintaining high energy density.
Implementation Method 1
the additive includes a compound represented by structural formula 1... forming a compact interface film to inhibit manganese ion transfer
Implementation Method 2
the separator is positioned between the positive electrode and the negative electrode... q is a porosity of the separator
Implementation Method 3
the generated manganese ions are dissolved in the electrolyte and transfer to the negative electrode, where they undergo ion exchange with lithium
Data Source
AI summary
To address the issue that the existing lithium ion battery with positive electrode containing manganese impacts battery performance, the application provides a lithium ion battery, which includes a positive electrode, a negative electrode, a non-aqueous electrolyte and a separator, and the separator is positioned between the positive and negative electrodes, the positive electrode includes a positive electrode material layer, the positive electrode material layer includes a lithium manganese-based positive electrode active material, the non-aqueous electrolyte includes a non-aqueous organic solvent, a lithium salt and an additive, and the additive includes a compound represented by structural formula 1:the lithium ion battery meets the following requirements:0.1≤q*m/p≤20;and 20≤q≤60,0.01≤m≤2,1.5≤p≤5;The lithium ion battery can enhances safety by reducing ion exchange between Mn2+ and lithium in the negative electrode, prevent manganese from damaging the negative electrode, and increasing electrode stability, ensuring high energy density and cycle performance.