Garnet Solid Electrolyte Morphology to Suppress Gelling
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Solution Overview
Problem
Solid electrolytes with a garnet-type structure containing Li, La, and Zr react with organic compounds, leading to gelling and uneven dispersion, which hinders uniform distribution.
Innovation Solution
A solid electrolyte composition with reduced basicity is developed, using specific mole proportions of Li, La, and Zr, along with optional elements like Mg and A, to minimize interaction with organic compounds and suppress gelling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a polymer electrolyte is used to enable flexibility and thin design, then the power storage device can be made flexible and thin, but the output voltage is limited to below 4.2 V due to electrochemical stability constraints
Solution Approach 1:
The patent uses a composite solid electrolyte made of polysulfone polymer matrix combined with lithium bis(fluorosulfonyl)imide (LiFSO3) salt and sulfur-containing filler particles. This composite structure provides both the flexibility/thinness of polymer electrolytes and the electrochemical stability needed for high-voltage operation, resolving the contradiction between shape adaptability and electrochemical reliability.
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by incorporating sulfur-containing fillers (such as sulfur, sulfur dioxide, or sulfur trioxide) into the polymer matrix. This compositional parameter change enhances the electrochemical stability window to above 4.2 V while maintaining the polymer's flexibility and processability, allowing both improved features to coexist.
2Quantity of substance
If lithium metal is used as the negative electrode to achieve high energy density, then the energy density increases, but lithium dendrite formation occurs causing safety issues
Solution Approach 1:
The patent introduces a solid polymer electrolyte as an intermediary layer between the lithium metal anode and the positive electrode. This solid electrolyte acts as a physical barrier that prevents lithium dendrites from growing and reaching the positive electrode, thereby eliminating the safety hazard while allowing lithium metal to provide high energy density.
Solution Approach 2:
The patent converts the potential harm of lithium dendrite formation into a benefit by using the solid electrolyte's mechanical properties to suppress dendrite growth. The solid electrolyte's composition and structure are designed to mechanically block dendrites, transforming what would be a harmful phenomenon into a controlled interface that enhances safety while maintaining high capacity.
3Length of stationary object
If the electrolyte volume is reduced to make the device thin, then the device thickness decreases, but the ionic conductivity may be insufficient
Solution Approach 1:
The patent employs a porous or microstructured solid electrolyte composition that provides high surface area and interconnected pathways for ion transport. The sulfur-containing filler particles create a network structure within the polymer matrix that facilitates lithium ion conduction even in thin films, maintaining high ionic conductivity despite reduced thickness.
Solution Approach 2:
The patent optimizes the compositional parameters of the solid electrolyte by adjusting the ratio of polymer matrix to lithium salt and sulfur-containing fillers. This parameter optimization ensures that even in thin film form, the electrolyte maintains sufficient ionic conductivity through enhanced ion transport pathways created by the composite structure.
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 solution reduces basicity, preventing gelling and ensuring uniform dispersion of the solid electrolyte, thereby enhancing the stability and performance of power storage devices.
Implementation Method 1
a specific ratio of lithium bis(fluorosulfonyl)imide and a sulfur-containing compound are put into a polymer skeleton
Implementation Method 2
lithium sulfite or lithium sulfate formed by reaction remain in an amorphous state
Data Source
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AI summary
To provide a solid electrolyte, an electrolyte composition, an electrolyte sheet, and a power storage device, in which gelling is suppressed. The solid electrolyte (18) has a garnet-type structure which contains Li, La, Zr, and O, in which, with respect to particles (21) of the electrolyte having a particle size equal to or greater than the particle size at which the cumulative value of frequency in a volume-based particle size distribution reaches 10%, a number average of degrees of envelope of particles is 0.8 or greater, the degree of envelope being defined as a ratio (area within a contour (22) of a particle/area within an envelope (23) of the particle). The electrolyte composition includes a solid electrolyte, an ionic liquid containing an imidazolium cation, a lithium salt, and a polymer having -CH2CF2-. The electrolyte sheet is formed of the electrolyte composition. The power storage device has an electrolyte layer formed of the electrolyte composition.