Quasi-Solid Electrolyte Concentration for Dendrite-Safe Lithium Cells
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Solution Overview
Problem
Conventional lithium metal and lithium-ion batteries face challenges such as dendrite formation, thermal runaway, and flammability due to volatile organic solvents, limiting their commercialization and energy density, especially in lithium-sulfur cells, which require safer and more efficient electrolytes to prevent internal shorting and explosions.
Innovation Solution
A quasi-solid electrolyte is introduced by increasing the lithium salt concentration in organic solvents to create a non-flammable electrolyte with a vapor pressure less than 0.01 kPa, preventing flammable gas molecules from initiating flames and enhancing lithium ion transference numbers for high energy density and long cycle life in lithium battery cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic liquid solvents are used in the electrolyte to enable lithium ion transfer, then the battery can operate with good ionic conductivity, but the electrolyte becomes flammable and volatile leading to thermal runaway and explosion
Solution Approach 1:
The patent changes the concentration parameter of lithium salt in the electrolyte from conventional low concentrations (0.5-2.0 M) to high concentrations (2.0-5.0 M). This parameter change transforms the electrolyte from a flammable liquid state to a non-flammable quasi-solid state, eliminating the safety hazards while maintaining ionic conductivity for battery operation
Solution Approach 2:
The patent creates a composite electrolyte system by combining high concentrations of lithium salt with organic liquid solvents. This composite approach produces a quasi-solid electrolyte that retains the beneficial ionic conductivity of liquid electrolytes while gaining the safety advantages of solid electrolytes, specifically non-flammability and reduced volatility
2Quantity of substance
If lithium metal is used as the anode to achieve high energy density, then the battery capacity increases significantly, but dendrites form during cycling causing internal shorting and thermal runaway
Solution Approach 1:
The patent changes the electrolyte concentration parameter to high lithium salt concentrations (2.0-5.0 M), which fundamentally alters the electrolyte's physical state to quasi-solid. This parameter change suppresses dendrite formation by creating a more stable interface with lithium metal, enabling safe cycling while maintaining high energy density
Solution Approach 2:
The patent converts the typically harmful effect of high viscosity in concentrated electrolytes into a beneficial quasi-solid state. This quasi-solid state provides mechanical stability that prevents dendrite growth and internal shorting, while still allowing sufficient lithium ion transport for high-rate charging and discharging
3Productivity
If conventional liquid electrolytes are used to ensure good ionic conductivity, then the battery operates efficiently, but the volatile solvents cause thermal runaway and explosion under abuse conditions
Solution Approach 1:
The patent changes the concentration parameter of lithium salt from conventional levels to high levels (2.0-5.0 M), which transforms the electrolyte's physical properties. This parameter change reduces volatility and eliminates flammability while maintaining adequate ionic conductivity for efficient battery operation
Solution Approach 2:
The patent induces a phase transition in the electrolyte from liquid to quasi-solid state through high lithium salt concentration. This phase transition fundamentally changes the safety profile by eliminating volatility and flammability, while the quasi-solid state maintains sufficient ion transport for battery productivity
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 quasi-solid electrolyte effectively suppresses flammability and dendrite growth, achieving high energy density and long cycle life in lithium battery cells, addressing safety concerns and improving performance beyond current lithium-ion and lithium-sulfur cell capabilities.
Implementation Method 1
enhancing lithium ion transference numbers for high energy density and long cycle life
Implementation Method 2
creating a non-flammable electrolyte with a vapor pressure less than 0.01 kPa, preventing flammable gas molecules from initiating flames
Data Source
AI summary
Provided is apparatus for introducing a quasi-solid electrolyte into one or a plurality of lithium battery cells, the apparatus comprising: (a) a cell-holding device to hold one or a plurality of lithium battery cells and is in a working relation to a liquid electrolyte-filling device that injects a liquid electrolyte into the battery cells, wherein the liquid electrolyte comprises a lithium salt dissolved in a first liquid solvent having a first lithium salt concentration from 0.001 M to 3.0 M (mole/L); and (b) a solvent vapor-removing device in a working relation to the cell-holding device, wherein the vapor-removing device comprises a pumping device to move solvent vapors away from the battery cells so that the electrolyte has a final lithium salt concentration higher than the first concentration and higher than 2.0 M. Also provided is a method of operating the apparatus.