Electrolyte Additive Pairing for High-Voltage Li-Ion Cycle Stability
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Solution Overview
Problem
Current lithium-ion battery electrolyte systems face deficiencies in cycle performance and storage performance, particularly at high voltage and high temperature, leading to reduced battery efficiency and safety.
Innovation Solution
Incorporating a multi-cyano six-membered N-heterocyclic compound and a sulfonate compound as additives in the electrolyte to passivate the positive electrode material, reduce gas production, and form a stable SEI film, thereby enhancing cycle and storage performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte system (lithium hexafluorophosphate with cyclic and chain carbonates) is used, then basic battery function is achieved, but cycle performance and storage performance deteriorate at high voltage and high temperature
Solution Approach 1:
The patent introduces a mediating substance (specific additive compound) that acts as an intermediary between the electrolyte and the positive electrode material. This additive forms a protective interface layer that prevents direct harmful interactions between the electrolyte and electrode at high temperatures, thereby improving cycle performance without sacrificing thermal stability.
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte by incorporating specific additives with controlled concentrations. This parameter change transforms the electrolyte's properties to enable stable operation at high voltages and temperatures, resolving the contradiction between reliability and temperature stability.
2Reliability
If conventional electrolyte system is used, then battery operation is maintained, but gas production increases and side reactions occur at high voltage
Solution Approach 1:
The patent converts the potentially harmful high-voltage conditions into a beneficial effect by using the additive to form a protective film that prevents further harmful reactions. The initial interaction at high voltage creates a stable interface that subsequently prevents gas production and side reactions, turning the harsh condition into a protective mechanism.
Solution Approach 2:
The additive serves as a mediating layer between the electrolyte and positive electrode material, preventing direct contact and harmful reactions. This intermediary substance suppresses gas evolution and side reactions that would otherwise occur at high voltages, improving storage performance.
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 combination of additives significantly improves cycle performance at high temperature and high voltage, reduces side reactions, and enhances storage performance by forming a stable protective film on the electrode surface.
Implementation Method 1
the additives can be adsorbed on catalytically active sites of the graphite surface
Implementation Method 2
form a more stable SEI film
Data Source
Figure 1~3
AI summary
The present disclosure relates to the field of energy storage materials, and specifically, to an electrolyte and an electrochemical device. The electrolyte includes an additive A and an additive B, the additive A is selected from a group consisting of multi-cyano six-membered N-heterocyclic compounds represented by Formula I-1, Formula 1-2 and Formula 1-3, and combinations thereof, and the additive B is at least one sulfonate compound. The electrochemical device includes the above electrolyte. The electrolyte of the present disclosure can effectively passivate surface activity of the positive electrode material, inhibit oxidation of the electrolyte, and effectively reduce gas production of the battery, meanwhile the electrolyte can be adsorbed on catalytically active sites of the graphite surface to form a stable SEI film, thereby effectively reducing side reactions. The electrochemical device using the electrolyte of the present disclosure has good high temperature and high voltage cycle performance and storage performance.