Li-Ion Battery Electrolyte Additives for High-Temperature Interface Stability
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Solution Overview
Problem
Lithium-ion batteries face challenges in safety and stability, particularly at high temperatures, due to intensified side reactions and gas production, which can lead to safety hazards and reduced reversible capacity.
Innovation Solution
An electrolyte composition that includes a compound of Formula I and an additive B, such as LiPF2O2, lithium bis(oxalato)borate, or lithium bis(trifluoromethanesulfonyl)imide, which polymerizes to form a protective film on electrodes, captures trace acids, and promotes lithium-ion transport, thereby enhancing thermal stability and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte compositions are used in lithium-ion batteries, then the batteries can operate under normal conditions, but the safety and stability deteriorate under high temperature environments due to intensified side reactions and gas production
Solution Approach 1:
The patent applies preliminary action by introducing the compound of Formula I and additive B into the electrolyte composition before high-temperature operation occurs. These additives proactively form protective films on electrode surfaces and capture trace acids before they can cause harmful side reactions or gas production during high-temperature cycling and storage, thereby preventing safety issues before they arise
Solution Approach 2:
The patent uses the compound of Formula I and additive B as intermediary substances that mediate between the electrolyte and electrode surfaces. These intermediaries form protective interface films that prevent direct harmful interactions between the electrolyte and electrodes at high temperatures, while also capturing trace acids through chemical buffering, thus resolving the contradiction between maintaining battery operation and preventing high-temperature degradation
2Duration of action of stationary object
If the electrolyte composition is optimized to improve high-temperature stability, then the cycle performance and storage performance are improved, but the device complexity increases due to multiple additive components
Solution Approach 1:
The patent applies universality by designing the compound of Formula I and additive B to perform multiple functions simultaneously: forming protective films on electrodes, capturing trace acids through chemical buffering, and enhancing overall electrolyte stability. This multi-functionality allows a single additive system to address multiple degradation mechanisms at high temperatures, improving cycle and storage performance without proportionally increasing composition complexity
Solution Approach 2:
The patent uses composite materials by combining the compound of Formula I with additive B in specific ratios (0.01-5% and 0.01-2% by mass respectively). This composite additive system creates synergistic effects where the two components work together to form more effective protective films and acid-capturing mechanisms, achieving enhanced high-temperature stability while maintaining manageable electrolyte formulation complexity through defined compositional ranges
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 composition significantly improves the high-temperature cycle performance, storage performance, and safety performance of lithium-ion batteries by inhibiting side reactions, reducing impedance, and maintaining the stability of solid and cathode electrolyte interfaces.
Implementation Method 1
The compound of Formula I can polymerize on the surfaces of positive and negative electrodes to generate a protective film with excellent stability
Implementation Method 2
an anhydride group in the compound of Formula I synchronously adheres to the electrode surface, and can capture the trace acid generated by the decomposition of lithium salt and other components in the electrolyte at high temperature
Implementation Method 3
the transport of lithium-ions between the active material and the electrolyte is promoted
Data Source
AI summary
An electrolyte includes a compound of Formula I and an additive B, and the additive B includes at least one of LiPF2O2, lithium bis(oxalato)borate, lithium difluoro(oxalato) borate, lithium bis(fluorosulfonyl)imide or lithium bis(trifluoromethanesulfonyl)imide.