Lithium Battery Anode SEI Film Formation via Propane Sultone
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Solution Overview
Problem
Lithium secondary batteries face performance degradation due to the excessive use of propane sultone-based compounds in electrolytes, which form passivation layers on anodes, leading to side reactions and capacity loss, especially under high temperature conditions.
Innovation Solution
A lithium secondary battery design that incorporates a controlled amount of propane sultone-based compounds, specifically 0.1–6 parts by weight in the electrolyte, combined with an anode active material having a specific surface area of 3 m2/g or less, to optimize the formation of a solid electrolyte interface (SEI) film, reducing degradation and enhancing safety and lifespan characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of propane sultone-based compound is used in the electrolyte to form a passivation layer on the anode, then the anode protection is improved, but side reactions increase and battery capacity is lost
Solution Approach 1:
The patent changes the concentration parameter of the propane sultone-based compound from conventional high levels (typically 10-20 parts by weight) to a controlled low level (0.1-6 parts by weight). This parameter change reduces side reactions and capacity loss while still forming sufficient passivation layer on the anode, thereby resolving the contradiction between anode protection and battery capacity maintenance.
2Productivity
If the specific surface area of the anode active material is increased to improve reaction efficiency, then the reaction rate is improved, but the amount of propane sultone-based compound needed for passivation increases
Solution Approach 1:
The patent changes the specific surface area parameter of the anode active material from conventional high values (typically >3 m2/g) to a controlled low value (≤3 m2/g). This parameter change reduces the total amount of passivation layer needed, thereby reducing the quantity of propane sultone-based compound required while still maintaining adequate anode protection and reaction efficiency.
3Reliability
If a large amount of propane sultone-based compound is used in the electrolyte, then the passivation layer formation is improved, but battery safety is degraded due to gas generation at high temperature
Solution Approach 1:
The patent changes the concentration parameter of the propane sultone-based compound to a controlled low level (0.1-6 parts by weight). This parameter change reduces the amount of compound available for decomposition reactions that produce gas, thereby improving battery safety at high temperatures while still forming sufficient passivation layer for anode protection.
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 controlled use of propane sultone-based compounds with electron-withdrawing groups forms a firm and dense SEI film, improving battery capacity, cycle life, and high-temperature storage characteristics by minimizing side reactions and maintaining thermal stability.
Implementation Method 1
a propane sultone-based compound known to improve the long-term safety and lifespan characteristics of a battery is used as a component for forming an electrolyte, the amount of the propane sultone-based compound needed to form a passivation layer on the surface of an anode upon the first charge cycle
Data Source
AI summary
Disclosed is a lithium secondary battery comprising a cathode, an anode, an electrolyte and a separator, wherein the anode comprises an anode active material having a specific surface area of 3 m2/g or less, and the electrolyte comprises 0.1˜6 parts by weight of a propane sultone-based compound based on 100 parts by weight of the electrolyte. The lithium secondary battery solves the problem of performance degradation caused by the use of an increased amount of a propane sultone-based compound required to form a SEI film on the surface of an anode upon the first charge cycle. Also, the lithium secondary battery can provide improved cycle characteristics and high-temperature storage characteristics.