Manganese Cathode Electrolyte Additive for High-Temperature Cycle Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium ion batteries with manganese-based positive electrode materials face issues of manganese ion dissolution, leading to capacity attenuation and poor high-temperature performance due to disproportionation reactions and electrolyte decomposition, which affect safety and cycle stability.
Innovation Solution
A secondary battery design incorporating a manganese-based positive electrode material with a specific additive compound in the non-aqueous electrolyte, controlled to form a passivation film that stabilizes the electrode structure, reduces manganese ion dissolution, and enhances the battery's high-temperature cycle and storage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high manganese content positive electrode active material is adopted to improve safety performance and reduce cost, then safety performance and cost are improved, but manganese ion dissolution occurs leading to capacity attenuation and poor cycle/storage performance
Solution Approach 1:
A compound containing sulfur atom is introduced as an intermediary substance in the non-aqueous electrolyte. This compound acts as a mediator that reacts with manganese ions to form insoluble manganese sulfide precipitates, thereby preventing manganese ion dissolution and its harmful effects on cycle performance while maintaining the safety benefits of high manganese content materials.
Solution Approach 2:
The harmful manganese ion dissolution is converted into a beneficial process by utilizing the sulfur-containing compound to transform soluble manganese ions into insoluble manganese sulfide precipitates. This converts the harmful dissolution effect into a controlled precipitation process that stabilizes the electrolyte and improves cycle performance.
2Reliability
If high manganese content positive electrode active material is adopted to improve safety performance and reduce cost, then safety performance and cost are improved, but manganese ion dissolution catalyzes electrolyte decomposition
Solution Approach 1:
The sulfur-containing compound serves as an intermediary that intercepts manganese ions before they can catalyze electrolyte decomposition. By forming insoluble manganese sulfide precipitates, it removes the catalytic manganese ions from the electrolyte system, thereby preventing the harmful electrolyte decomposition reaction while preserving the safety advantages of high manganese content materials.
3Reliability
If high manganese content positive electrode active material is adopted to improve safety performance and reduce cost, then safety performance and cost are improved, but capacity attenuation occurs due to manganese ion dissolution
Solution Approach 1:
The harmful manganese ion dissolution that leads to capacity attenuation is transformed into a beneficial precipitation process. The sulfur-containing compound causes manganese ions to precipitate as insoluble manganese sulfide, converting the harmful dissolution effect into a controlled precipitation mechanism that stabilizes the electrolyte composition and maintains capacity retention while preserving the safety benefits of high manganese content materials.
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 solution effectively improves the safety and stability of lithium ion batteries by forming a protective film that inhibits manganese ion dissolution and electrolyte decomposition, leading to better high-temperature cycle and storage performance while maintaining high capacity retention and rate performance.
Implementation Method 1
the compound represented by structural formula 1 can form a dense passivation film at the positive electrode interface, hence stabilizes the positive electrode structure and reduces the dissolution of manganese ions
Implementation Method 2
reduces the dissolution of manganese ions, thus reducing the oxidation of the electrolyte at the positive electrode interface
Implementation Method 3
the compound represented by structural formula 1 can also form a protective film on the negative electrode, significantly reducing the damage of dissolved manganese ions to the negative electrode SEI film structure
Implementation Method 4
effectively inhibiting the continuous decomposition of electrolyte at the negative electrode interface
Data Source
AI summary
In order to solve the problem that the existing manganese-based positive electrode material battery has insufficient high-temperature cycle and high-temperature storage performances due to the dissolution of manganese ions, the present application provides a secondary battery, comprising a positive electrode, a negative electrode and a non-aqueous electrolyte, the positive electrode comprises a positive electrode material layer containing a positive electrode active material, the positive electrode active material comprises a manganese-based material, and the non-aqueous electrolyte comprises a solvent, an electrolyte salt and an additive, and the additive comprises a compound represented by structural formula 1:the secondary battery meets the following requirements:0.05≤100×W×u/(q×s)≤5;and 2.0 g/Ah≤W≤4.5 g/Ah, 0.05%≤u≤3.5%, 5%≤q≤65%, 10 mg/cm2≤s≤30 mg/cm2.The secondary battery has a high capacity retention rate in the cycle and high-temperature storage processes, and has good cycle and storage performances.