Lithium Battery Electrolyte Anion for High Temperature Storage
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Solution Overview
Problem
Lithium metal secondary batteries face capacity deterioration due to precipitation and dissolution reactions, and existing electrolyte salts like LiPF6 have poor thermal stability and conductivity issues, limiting high temperature storage characteristics and discharge performance.
Innovation Solution
A battery design incorporating an anode capacity component by both lithium insertion/extraction and precipitation/dissolution, with an electrolyte containing anions expressed by the chemical formula [B(RF1)(RF2)(RF3)RF4]−, which improves high temperature storage characteristics and reduces inner resistance when moisture content is minimized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiPF6 is used as electrolyte salt, then high conductivity is achieved, but thermal stability deteriorates leading to poor high temperature storage characteristics
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte salt from conventional LiPF6 to LiBF4, and further to novel fluorinated borate salts with specific molecular structures. This parameter change achieves both high thermal stability (resistance to decomposition at elevated temperatures) and high ionic conductivity, resolving the contradiction between thermal stability and conductivity.
Solution Approach 2:
The patent develops composite electrolyte systems by combining fluorinated borate salt anions with specific cations (Li+, Na+, K+, etc.) to create new electrolyte materials that exhibit synergistic properties. The composite structure of the electrolyte salt molecule itself (combining boron, fluorine, and oxygen in specific arrangements) provides both thermal stability and ionic conductivity simultaneously.
2Reliability
If LiPF6 is used as electrolyte salt, then high conductivity is achieved, but oxidation stability deteriorates limiting discharge characteristics at high voltage
Solution Approach 1:
The patent modifies the electrolyte salt composition by replacing LiPF6 with fluorinated borate salts that have higher oxidation potentials. The specific molecular structure parameters (fluorinated groups, borate core) are optimized to achieve both oxidation stability and high ionic conductivity, enabling stable discharge characteristics at voltages of 4V or higher.
3Reliability
If LiClO4 or LiAsF6 is used as electrolyte salt, then high conductivity is achieved, but charge and discharge characteristics deteriorate due to reactivity with lithium metal
Solution Approach 1:
The patent changes the electrolyte salt from LiClO4 or LiAsF6 to fluorinated borate salts with specific molecular structures that exhibit lower chemical reactivity toward lithium metal. The fluorinated groups and borate core structure provide kinetic stability against lithium metal while maintaining high ionic conductivity, thereby improving charge and discharge characteristics.
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 battery achieves enhanced high temperature storage characteristics and improved discharge performance by using the specific anionic electrolyte, which stabilizes the electrolyte and enhances lithium metal precipitation and dissolution processes.
Implementation Method 1
precipitation and dissolution reaction of the lithium metal is utilized for anode reaction
Implementation Method 2
one wherein LiPF6 as an electrolyte salt is dissolved in a carbonic acid ester nonaqueous solvent such as propylene carbonate and diethyl carbonate has been widely used in view of its high conductivity
Implementation Method 3
a material such as carbon materials capable of inserting and extracting lithium (Li) is used for an anode
Data Source
AI summary
The invention provides a battery, which can improve battery characteristics such as high temperature storage characteristics. The battery comprises a battery device, wherein a cathode and an anode are wound with a separator in between. The anode contains an anode material capable of inserting and extracting Li as an anode active material. An electrolytic solution is impregnated in the separator. The electrolytic solution contains a solvent, and an electrolyte salt such as Li[B(CF3)4] dissolved in the solvent, which is expressed by a chemical formula of Li[B(RF1)(RF2)(RF3)RF4]RF 1, RF 2, RF 3, and RF 4 represent a perfluoro alkyl group whose number of fluorine or carbon is from 1 to 12, respectively. Consequently, high temperature storage characteristics are improved.