Li-Ion Battery Electrolyte Composition for High-Nickel Fast Charging
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Solution Overview
Problem
Conventional electrolytes fail to balance the requirements of high-nickel and high-silicon lithium-ion batteries with fast-charging performance, leading to increased material reactivity and secondary reactions.
Innovation Solution
An electrolyte formulation comprising cyclic carbonates, specifically fluoroethylene carbonate and ethylene carbonate, along with lithium salts like lithium hexafluorophosphate and additives such as ethylene sulfate, optimized to enhance electrical conductivity and desolvation capability, thereby improving fast-charging capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte formulations are used, then the electrolyte can accommodate high-nickel and high-silicon materials, but the fast-charging performance deteriorates due to increased material reactivity and secondary reactions
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing specific additives (lithium difluorophosphate and vinylene carbonate) and optimizing the ratio of cyclic carbonate to chain carbonate. This parameter adjustment reduces material reactivity while maintaining fast-charging capability, resolving the contradiction between electrolyte stability and charging speed
Solution Approach 2:
The patent creates a composite electrolyte system by combining multiple components: cyclic carbonates (EC, PC), chain carbonates (DMC, DEC), and specific additives (lithium difluorophosphate, vinylene carbonate). This composite formulation synergistically addresses both stability and fast-charging requirements that single-component electrolytes cannot achieve
2Quantity of substance
If high-nickel and high-silicon materials are used to enhance energy density, then the battery energy density improves, but the material reactivity and secondary reactions increase
Solution Approach 1:
The patent uses vinylene carbonate and lithium difluorophosphate as intermediary substances that form protective interface layers between the high-nickel/high-silicon electrodes and the electrolyte. These intermediaries suppress direct contact and secondary reactions, reducing harmful effects while preserving the high energy density benefits
3Power
If the cyclic carbonate content is increased to improve electrical conductivity, then the fast-charging capability improves, but the viscosity increases which may affect ion transport
Solution Approach 1:
The patent optimizes the cyclic carbonate content parameter within a specific range (20-30%) and adjusts the ratio between different cyclic carbonates (EC and PC). This parameter optimization achieves the desired electrical conductivity while controlling viscosity to maintain proper ion transport properties
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 optimized electrolyte achieves a balance between high electrical conductivity and rapid desolvation, enhancing the fast-charging capability of lithium-ion batteries while maintaining stability, with charging capabilities greater than or equal to 3 C and operating voltages up to 4.15V.
Implementation Method 1
The cyclic carbonate includes fluoroethylene carbonate and ethylene carbonate. The content of the fluoroethylene carbonate in the electrolyte is greater than or equal to 6%. The content of the ethylene carbonate in the electrolyte is greater than or equal to 2%
Implementation Method 2
The lithium salt includes lithium hexafluorophosphate and lithium difluoro sulfonyl imide. The content of the lithium hexafluorophosphate in the electrolyte for lithium-ion battery is 13% to 17%. The content of the lithium difluoro sulfonyl imide in the electrolyte for lithium-ion battery is less than or equal to 2%
Data Source
AI summary
Disclosed are an electrolyte for a lithium-ion battery and a lithium-ion battery, and the present disclosure specifically relates to the field of electrolyte technology. The electrolyte includes: an organic solvent, lithium salt and an additive. The organic solvent includes cyclic carbonate. The content of the cyclic carbonate in the electrolyte is 20% to 30%. The cyclic carbonate includes fluoroethylene carbonate and ethylene carbonate. The content of the fluoroethylene carbonate in the electrolyte is greater than or equal to 6%. The content of the ethylene carbonate in the electrolyte is greater than or equal to 2%. The electrolyte of the present disclosure, while enhancing fast-charging capability, does not affect other performance of the battery, and may achieve a balance between high-nickel and high-silicon battery and fast-charging capability.