LiBOB Plastic Crystal Electrolyte for High-Voltage Stability
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Solution Overview
Problem
Current lithium-based electrochemical devices using liquid electrolytes face challenges with packaging, cost, size, and safety, while solid polymer electrolytes have low conductivity at room temperature, limiting their application in high-energy density batteries.
Innovation Solution
The use of a lithium bioxalato borate salt (Li[C2O4]2B) in a solid ionic electrolyte with an organic plastic crystal matrix provides a stable electrolyte interface over a broader potential window, enhancing ionic conductivity and compatibility with lithium metal, allowing for higher energy density and faster stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer electrolytes are used to improve safety and mechanical characteristics, then safety and mechanical properties are improved, but ionic conductivity at room temperature deteriorates
Solution Approach 1:
The patent changes the physical state and molecular arrangement parameters of the electrolyte by using plastic crystal phases instead of conventional polymer matrices. This parameter change enables the electrolyte to maintain solid-state safety while achieving high ionic conductivity through the unique rotational and translational disorder characteristics of plastic crystals
Solution Approach 2:
The patent creates a composite electrolyte system combining plastic crystal formers (succinonitrile, adiponitrile) with lithium salts (LiBF4, LiCF3SO3). This composite approach integrates the mechanical stability of solids with the high ionic conductivity needed for room temperature operation, achieving both safety and performance
2Quantity of substance
If Li(CF3SO2)2N or LiBF4 salts are used in succinonitrile plastic crystal electrolytes to achieve high ionic conductivity, then ionic conductivity is improved, but electrochemical stability window deteriorates (limiting voltage to about 2 V)
Solution Approach 1:
The patent introduces LiBOB (lithium bis(oxalato)borate) as an intermediary substance that mediates between the lithium metal anode and the succinonitrile plastic crystal electrolyte. This intermediary forms a stable solid electrolyte interface (SEI) layer that prevents direct harmful interactions while maintaining ionic conductivity, enabling both high conductivity and broad electrochemical stability window simultaneously
3Use of energy by moving object
If lithium metal anodes are used to achieve highest theoretical capacity density, then energy content is improved, but dendrite formation and safety issues worsen
Solution Approach 1:
The patent applies beforehand cushioning by forming a stable solid electrolyte interface (SEI) layer using LiBOB before lithium dendrites can form. This protective interface acts as a cushion that prevents dendrite growth and stabilizes the lithium metal anode, enabling safe use of high-capacity lithium metal while maintaining high energy content
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 LiBOB-based solid electrolyte achieves a wider electrochemical stability window of about 4.6 V or greater, faster stabilization, and higher energy density, maintaining excellent mechanical and chemical stability, and compatibility with lithium metal, while reducing initial AC impedance and stabilization time.
Implementation Method 1
Plastic crystals are mesophases formed mainly by quasi-spherical or disk-like molecules exhibiting rotational and/or orientational disorder while retaining the long-range translational order
Implementation Method 2
With conductivities as high as 10−3 S·cm−1 at room temperature and good mechanical properties, plastic crystal electrolytes are one of the most promising alternatives to liquid or gelled electrolytes
Implementation Method 3
The use of lithium bioxalato borate salt (Li[C2O4]2B) in a solid ionic electrolyte having an organic plastic crystal matrix provides a stable electrolyte interface over a broader potential window
Implementation Method 4
enhancing ionic conductivity and compatibility with lithium metal, allowing for higher energy density and faster stabilization
Data Source
AI summary
A solid ionic electrolyte having an organic plastic crystal solvent (e.g. succinonitrile) doped with lithium bioxalato borate salt (LiBOB) may be used in an electrochemical device. Electrochemical devices are disclosed having a cathode, an anode, and a solid ionic electrolyte having a neutral organic plastic crystal solvent doped with LiBOB alone or in combination with another lithium salt. Such devices have a stable electrolyte interface over a broad potential window combined with high energy density delivery capacity and, in one example, the favorable properties of a neutral organic plastic crystal matrix such as succinonitrile.