Cosolvent Electrode Slurry for Sulfide Battery Chemical Stability
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Solution Overview
Problem
Existing solvents used in the manufacturing of sulfide solid-state batteries, such as N-methylpyrrolidone (NMP), react with other ingredients, posing a challenge in preparing electrolytes without adverse reactions.
Innovation Solution
A cosolvent slurry system comprising a low-polar solvent with a dipole moment of less than 4 and a boiling point greater than 100°C, combined with an ether-based solvent, is used to mix with active materials, electrically conducting materials, and a polymeric binder to form an electrode-forming slurry, preventing reactions with sulfide solid-state battery ingredients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If N-methylpyrrolidone (NMP) is used as the solvent, then the electrode slurry can be effectively formed, but the solvent reacts with sulfide solid-state battery ingredients, compromising chemical stability
Solution Approach 1:
The patent changes the key parameter of solvent polarity from high (NMP) to low (cosolvent system with dipole moment < 4). This parameter change reduces the reactivity of the solvent with sulfide ingredients while maintaining sufficient solubility for electrode materials through the cosolvent combination, thus resolving the contradiction between manufacturability and chemical stability
Solution Approach 2:
The patent employs a composite solvent system combining multiple solvents with complementary properties: one solvent provides solubility for active materials while another provides chemical inertness. This composite approach allows the system to achieve both effective slurry formation and high chemical stability, overcoming the limitations of single solvents
2Reliability
If a low-polar solvent with dipole moment less than 4 is used, then chemical reactivity with battery ingredients is reduced, but solvent selection and formulation become more complex
Solution Approach 1:
The patent applies local quality by assigning different functional roles to different solvents in the cosolvent system. One solvent component is optimized for dissolving active materials while another is optimized for chemical inertness. This functional differentiation allows each component to excel at its specific task, reducing overall system complexity despite the multi-component nature
Solution Approach 2:
The patent uses one solvent as an intermediary that bridges the gap between the reactive sulfide ingredients and the low-polar solvent. This intermediary solvent maintains chemical stability while facilitating the dissolution of electrode materials, thus simplifying the overall formulation process by providing a clear functional division of labor
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 proposed cosolvent system effectively prevents reactions between the electrode and electrolyte, ensuring the chemical structure and ionic conductivity of the sulfide solid-state electrolyte are retained, thereby enhancing the performance and stability of the batteries.
Implementation Method 1
A cosolvent slurry system comprising a low-polar solvent with a dipole moment of less than 4 and a boiling point greater than 100°C, combined with an ether-based solvent, is used to mix with active materials, electrically conducting materials, and a polymeric binder to form an electrode-forming slurry, preventing reactions with sulfide solid-state battery ingredients
Implementation Method 2
The electrode-forming slurry is disposed on a current collector and subjecting the current collector to an increased temperature. The electrode-forming slurry present on the current collector is dried to form the electrode
Data Source
AI summary
A method of manufacturing an electrode-forming slurry includes mixing together an active material, an electrically conducting material and optionally a solid state electrolyte with a low-polar solvent. The low-polar solvent has a dipole moment of less than 4 and a boiling point greater than 100° C. to form a first slurry, where the active material is an anode active material or a cathode active material. A polymeric binder and an ether-based solvent are mixed to form second slurry. The first slurry and the second slurry are mixed to form the electrode-forming slurry.