Non-Aqueous Electrolyte Additives for Stable Lithium Battery Cathodes
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Solution Overview
Problem
Lithium secondary batteries face issues with mechanical and chemical stability due to side reactions between the cathode active material and the electrolyte, leading to deteriorated cycle life characteristics and reduced operational stability.
Innovation Solution
A non-aqueous electrolyte comprising a non-aqueous organic solvent, a lithium salt, and an additive containing a sulfonyl group with two phosphorus atoms, along with an auxiliary alkyl sultone compound, is used to enhance mechanical and chemical stability, promoting lithium ion and electron migration and suppressing side reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte is used in lithium secondary batteries, then the battery can operate with basic functionality, but mechanical and chemical stability deteriorates due to side reactions between cathode active material and electrolyte
Solution Approach 1:
The patent introduces a novel additive containing phosphorus atoms as an intermediary substance between the cathode active material and the electrolyte. This additive forms a protective interface layer that mediates the interaction, preventing direct harmful side reactions while maintaining ionic conductivity. The phosphorus-containing compound acts as a buffer that stabilizes the electrode-electrolyte interface.
Solution Approach 2:
The patent employs a composite electrolyte system combining conventional electrolyte components with a novel phosphorus-containing additive. This composite approach creates a multi-functional electrolyte that maintains the beneficial properties of conventional electrolytes while adding protective and stabilizing functions through the phosphorus compound.
2Power
If the battery operates under extreme conditions such as high temperature, then power delivery may be maintained, but cycle life characteristics deteriorate due to accelerated degradation
Solution Approach 1:
The phosphorus-containing additive provides beforehand cushioning by forming a protective film on the cathode surface before extreme conditions cause severe degradation. This pre-formed protective layer cushions the electrode against thermal and mechanical stress during high-temperature operation and extreme charge/discharge rates, preserving cycle life.
Solution Approach 2:
The patent utilizes parameter changes in the electrolyte composition by incorporating the phosphorus-containing additive, which alters the chemical and physical parameters of the electrolyte system. This modification changes the stability characteristics and reaction kinetics, enabling the battery to maintain performance under extreme conditions without accelerating degradation.
3Ease of manufacture
If the electrolyte composition is simplified for ease of manufacture, then production cost decreases, but operational stability and electrochemical characteristics deteriorate
Solution Approach 1:
The patent applies local quality by concentrating the phosphorus-containing additive at the electrode-electrolyte interface rather than uniformly distributing complex additives throughout the entire electrolyte volume. This localized approach provides maximum protective benefit at the critical interface while maintaining simple bulk electrolyte composition for ease of manufacture.
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 improves initial capacity, high-temperature storage characteristics, and cycle life characteristics of lithium secondary batteries by reducing resistance and stabilizing the battery under extreme conditions.
Implementation Method 1
promoting lithium ion and electron migration
Implementation Method 2
promoting lithium ion and electron migration
Implementation Method 3
suppressing side reactions
Data Source
Figure 1~2
AI summary
Embodiments of the present invention provide a non-aqueous electrolyte and a lithium secondary battery including the same. The non-aqueous electrolyte includes a non-aqueous organic solvent, a lithium salt, and an additive including a sulfonyl compound containing a sulfonyl group and two phosphorus atoms within one molecule.