Low-Viscosity Electrolyte for Thick LFP-Li Batteries
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Solution Overview
Problem
Conventional carbonate and high-concentration electrolytes used in LFP-Li batteries are incompatible with thick electrodes and lithium anodes, leading to poor electrochemical performance, including short battery life and reduced charge/discharge capacity.
Innovation Solution
A low-viscosity electrolyte comprising a low-viscosity main salt, lithium-based functional salts, and a cyclic ether solvent is used, which forms a stable solid electrolyte interphase, enhancing Li ion conductivity and improving electrochemical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carbonate electrolyte or high-concentration electrolyte is used in LFP-Li batteries, then the battery can be assembled with standard components, but the electrochemical performance deteriorates due to incompatibility with thick electrodes and lithium anodes
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a specific cyclic ether solvent (1,3-dioxolane or 1,4-dioxane) in combination with carbonate solvents and lithium salts. This parameter change transforms the electrolyte's compatibility characteristics, enabling it to work effectively with thick electrodes and lithium anodes while maintaining good electrochemical performance.
Solution Approach 2:
The patent creates a composite electrolyte system by combining multiple components: cyclic ether solvent (1,3-dioxolane or 1,4-dioxane), carbonate solvents (EC, PC, DMF, DMSO), and lithium salts (LiPF6, LiBF4, LiClO4). This composite approach synergistically improves both compatibility with thick electrodes/lithium anodes and electrochemical performance.
2Quantity of substance
If thick electrodes are used to increase capacity, then the energy density improves, but the electrochemical performance deteriorates when using conventional electrolytes
Solution Approach 1:
The patent modifies the electrolyte's physical and chemical parameters by incorporating cyclic ether solvents with specific dielectric constants and viscosities. These parameter changes enable the electrolyte to effectively penetrate thick electrodes and facilitate lithium ion transport, thereby maintaining high electrochemical performance even with increased capacity loading.
3Productivity
If lithium anode is used to improve stripping/plating efficiency, then the battery capacity improves, but the battery life deteriorates with conventional electrolytes
Solution Approach 1:
The patent changes the electrolyte composition parameters by adding cyclic ether solvents that form stable solid electrolyte interphase (SEI) on lithium anodes. This parameter modification improves lithium stripping/plating efficiency while simultaneously enhancing battery life by preventing dendrite formation and electrolyte decomposition.
Solution Approach 2:
The cyclic ether solvent acts as an intermediary that mediates between the lithium anode and the carbonate electrolyte. It forms a protective interface layer that enables efficient lithium ion transport while protecting the lithium anode from direct contact with the carbonate electrolyte, thereby improving both stripping/plating efficiency and battery life.
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 new electrolyte improves Li ion conductivity and anode stripping/plating efficiency, resulting in improved electrochemical performance and extended battery life for thick LFP-Li batteries.
Implementation Method 1
Rechargeable lithium-ion batteries utilize an electrolyte to carry or conduct lithium cations (Li+) between a cathode active material and an anode active material.
Implementation Method 2
A low-viscosity electrolyte comprising a low-viscosity main salt, lithium-based functional salts, and a cyclic ether solvent is used, which forms a stable solid electrolyte interphase, enhancing Li ion conductivity and improving electrochemical performance.
Data Source
AI summary
An electrolyte for a thick LFP-Li battery system is provided. The electrolyte includes a low-viscosity main salt, at least one lithium-based functional salt, and a solvent including a low viscosity solvent mixed with a cyclic ether solvent. The low-viscosity main salt includes at least one of LiTFSI or a lithium salt.