Cyano-functionalized Ionic Liquid Electrolyte Additives for Li-Ion Batteries
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Solution Overview
Problem
Lithium-ion batteries face challenges in achieving high volumetric energy densities and long cycling life due to instability of the cathode structure and electrolyte degradation, leading to rapid interfacial impedance growth and capacity decay.
Innovation Solution
The development of an electrolyte fluid comprising specific compounds, such as cyano-functionalized ionic liquids, electrolyte salts, and solvents, which form stable cathode-electrolyte and solid-electrolyte interphases, enhancing the battery's discharge capacity and energy retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional electrolytes are used to achieve high volumetric energy density, then battery capacity increases, but cathode structure instability and electrolyte degradation occur, leading to rapid interfacial impedance growth and capacity decay
Solution Approach 1:
The patent introduces a mediator substance (a specific compound with formula (I) containing a cyano group and sulfone group) that acts as an intermediary between the cathode and conventional electrolyte. This mediator forms a stable interfacial layer that prevents direct harmful interactions between the cathode structure and electrolyte, thereby maintaining high energy density while improving cycling stability and reducing impedance growth.
2Power
If high voltage cathode materials are used to increase energy density, then battery performance improves, but cathode structure instability increases, causing faster capacity decay
Solution Approach 1:
The patent changes the chemical parameters at the cathode-electrolyte interface by introducing a compound with specific functional groups (cyano and sulfone groups in formula (I)). This parameter change creates a new interfacial environment that stabilizes the cathode structure during high-voltage operation, preventing structural degradation while maintaining high 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 proposed electrolyte fluid improves the battery's specific discharge capacity and energy retention, reducing internal resistance and extending cycle life, resulting in higher energy retention and reduced impedance growth.
Implementation Method 1
form stable cathode-electrolyte (CEI) and/or solid-electrolyte interphases (SEI)
Implementation Method 2
Li-ion batteries are widely used as the power sources in consumer electronics
Data Source
AI summary
This disclosure relates generally to battery cells, and more particularly, electrolyte additives for use in lithium ion battery cells.