Ionogel Electrolyte for Solid-State Batteries
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Solution Overview
Problem
Current ionogels used as electrolytes in batteries face issues such as high shrinkage, low solidity leading to electronic short circuits, and excessive water content, which limits their application, especially with lithium, and result in low energy density in solid-state batteries due to their relatively low conductivity.
Innovation Solution
A method for preparing high-energy all-solid-state batteries using ionogels involves casting a medium containing an ionic liquid, a lithium or sodium salt, and an inorganic molecular precursor with hydrolyzable groups, followed by in situ polycondensation to form a continuous iono-covalent network within the electrode, reducing water content to less than 50 ppm for enhanced stability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ionogels are used as electrolytes, then ionic conductivity is achieved, but high shrinkage and low solidity occur leading to electronic short circuits
Solution Approach 1:
The patent employs a composite material system combining an ionic liquid (EMIM-TFSI) with a polymer matrix (PVDF-HFP) to create an ionogel electrolyte. This composite structure provides both ionic conductivity through the ionic liquid phase and mechanical solidity through the polymer network, preventing electrode short circuits while maintaining ion transport. The composite approach resolves the contradiction by integrating the beneficial properties of both materials.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the ionogel by adjusting the ratio of ionic liquid to polymer, controlling the gelation process, and optimizing the composition to achieve the desired balance between ionic conductivity and mechanical strength. By carefully controlling parameters such as ionic liquid content, polymer molecular weight, and crosslinking density, the patent achieves both high conductivity and sufficient solidity to prevent short circuits.
2Reliability
If conventional ionogels are used as electrolytes, then ionic conductivity is achieved, but excessive water content limits application with lithium
Solution Approach 1:
The patent employs anhydrous conditions and inert atmosphere techniques during the preparation of the ionogel electrolyte to prevent water contamination. The ionic liquid EMIM-TFSI and polymer PVDF-HFP are handled under conditions that exclude moisture, and the gelation process is conducted in a controlled environment. This inert approach ensures the final ionogel has minimal water content, making it compatible with lithium electrodes while maintaining ionic conductivity.
3Reliability
If solid-state batteries are used, then safety is improved, but low conductivity results in low energy density
Solution Approach 1:
The patent uses an ionic liquid-based ionogel as an intermediary material that bridges the gap between conventional liquid electrolytes and traditional solid electrolytes. The ionogel maintains the high ionic conductivity characteristic of liquid electrolytes while providing the solid-state safety benefits. This intermediary approach allows solid-state batteries to achieve high energy density by enabling thicker electrode designs without sacrificing conductivity, thus resolving the contradiction between safety and 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 resulting ionogels are stable up to 250°C, exhibit high ionic conductivity, and have minimal volume shrinkage, enabling the creation of high-energy, efficient all-solid-state batteries with improved safety and performance.
Implementation Method 1
a step of polycondensation in situ of at least one inorganic molecular precursor
Implementation Method 2
exhibit remarkable properties such as zero volatility, high ionic conductivity
Implementation Method 3
The sol-gel process is well known from the prior art, simple to implement, takes place under mild conditions and facilitates the shaping of materials
Data Source
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AI summary
The invention relates to an accumulator or battery including at least one composite electrode including a step of pouring a medium comprising at least one ionic liquid and a lithium, sodium or magnesium salt with at least one inorganic molecular precursor or a polymerisable monomer, said medium being in excess, and a step of in situ polycondensation or polymerisation.