Polycarbonate Solid Electrolyte Synthesis via Methane Sulfonic Acid
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Solution Overview
Problem
Conventional methods for synthesizing solid electrolytes for lithium batteries, such as those using stannous octanoate as a catalyst, require long reaction times, high energy consumption, and result in polymers with structural defects and residual catalyst impurities, which can negatively impact battery performance and durability.
Innovation Solution
The synthesis of aliphatic polycarbonates, like poly(trimethylene carbonate) and its copolymers, using methane sulfonic acid as a catalyst or microwave irradiation without a catalyst, to produce solid electrolytes with controlled chemical structure and high purity, which are then incorporated into composite electrodes for lithium batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If stannous octanoate is used as a catalyst for ring opening polymerization of cyclic carbonates, then the polymerization reaction can proceed, but the reaction requires long reaction times and high energy consumption
Solution Approach 1:
The patent changes the catalyst from stannous octanoate to methane sulfonic acid, which operates under different reaction conditions (lower temperature, shorter time). This parameter change in catalyst type enables the same polymerization reaction to proceed much faster and with lower energy input, directly resolving the contradiction between reaction speed and time/energy consumption
Solution Approach 2:
The patent replaces the traditional thermal polymerization mechanism (using stannous octanoate catalyst requiring high temperature and long time) with an alternative chemical mechanism (using methane sulfonic acid catalyst). This substitution of the reaction mechanism allows the polymerization to proceed under milder, faster conditions without compromising the polymerization completeness
2Ease of manufacture
If stannous octanoate catalyst is used for polymerization, then the polymerization can be catalyzed effectively, but residual catalyst impurities remain in the polymer
Solution Approach 1:
The patent extracts or removes the harmful residual catalyst (stannous octanoate) from the polymer product by replacing it with methane sulfonic acid catalyst, which can be more easily removed or decomposed. This extraction of the problematic catalyst residue directly improves the polymer purity while maintaining catalytic efficiency during the reaction process
Solution Approach 2:
The patent uses methane sulfonic acid as a temporary catalyst that can be easily removed or decomposed after serving its purpose during polymerization. Unlike stannous octanoate which remains as a persistent residual impurity, the methane sulfonic acid catalyst serves its function and then can be eliminated, leaving a purer final product while maintaining ease of manufacture during the reaction
3Productivity
If conventional polymerization methods are used, then solid electrolytes can be produced, but the polymers contain structural defects
Solution Approach 1:
The patent changes the polymerization parameters including catalyst type (to methane sulfonic acid), reaction temperature, and reaction time. These parameter changes lead to a more controlled polymerization process that reduces structural defects in the resulting polymer chains, while still maintaining high productivity in electrolyte production
Solution Approach 2:
The patent performs preliminary optimization of the polymerization conditions using methane sulfonic acid catalyst and controlled reaction parameters before the actual electrolyte production. This preliminary action ensures that the polymer chains are formed with minimal structural defects from the outset, preventing quality issues rather than correcting them later, thus maintaining both high production efficiency and structural quality
4Quantity of substance
If high molecular weight polycarbonates are synthesized by ring opening polymerization, then the solid electrolyte can be formed, but the synthesis requires high temperatures and long reaction times
Solution Approach 1:
The patent changes the catalyst to methane sulfonic acid and adjusts reaction parameters (temperature, time) to achieve a more efficient polymerization pathway. This parameter change allows the synthesis of high molecular weight polycarbonates at lower temperatures and shorter times, directly reducing the energy consumption while maintaining the required polymer quantity and molecular weight
Solution Approach 2:
The patent substitutes the traditional high-energy thermal polymerization mechanism with a more efficient catalytic mechanism using methane sulfonic acid. This substitution replaces the energy-intensive process with a chemically more efficient pathway that achieves the same high molecular weight polymer synthesis with significantly reduced energy input
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
This approach results in composite electrodes with improved ionic conductivity, electrochemical stability, and flexibility, enabling high-energy-density battery performance over a wide temperature range without the adverse effects of residual catalysts.
Implementation Method 1
using methane sulfonic acid (MSA) as a catalyst
Implementation Method 2
in the absence of catalyst under microwave irradiation
Data Source
Figure 1a~2b
Figure 3a~3c
Figure 4a~5
AI summary
Composite electrode comprising a solid electrolyte based on polycarbonates. The invention relates to a composite electrode comprising: - at least one solid electrolyte consisting of one or more (co)polymers obtained by ring-opening (ROP) (co)polymerization of at least one cyclic carbonate of five to eight members and, optionally, of at least one lactone of five to eight members, catalyzed by methanesulfonic acid or carried out under microwave irradiation in the absence of a catalyst; the hydroxyl functions at the end of the chain of said (co)polymer(s) being optionally protected; and at least one alkali or alkaline earth metal salt, in particular a lithium salt; - at least one active electrode material; and - optionally, one or more electronically conductive additives and/or one or more binders.It also relates to an ink and a process for the preparation of this composite electrode, as well as its use in an electrochemical system, in particular in a lithium battery.