Polycarbonate Solid Electrolyte Synthesis Without Metal Catalysts
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Solution Overview
Problem
Existing synthesis routes for aliphatic polycarbonates, such as ring-opening polymerization catalyzed by stannous octanoate, result in high energy consumption, uncontrolled polymerization, and the presence of metal catalysts that can adversely affect the performance and durability of rechargeable lithium batteries, with limited ionic conductivity and electrochemical stability.
Innovation Solution
A new synthesis method using methanesulfonic acid as a catalyst for ring-opening polymerization of cyclic carbonates and lactones, optionally initiated by a compound with hydroxyl functions, followed by protection and purification of the polymer, to produce aliphatic polycarbonates with controlled structure and high purity, suitable for forming solid electrolytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ring-opening polymerization is catalyzed by stannous octanoate, then polymerization can proceed, but energy consumption is high and polymerization is uncontrolled
Solution Approach 1:
The patent changes the catalytic parameters by replacing stannous octanoate with boronic acid catalysts and adjusts reaction conditions (temperature, solvent, monomer-to-catalyst ratio) to achieve controlled polymerization at lower energy input while maintaining high productivity
2Productivity
If stannous octanoate is used as catalyst, then polymerization proceeds, but metal catalysts adversely affect battery performance and durability
Solution Approach 1:
The patent extracts the harmful metal catalyst (stannous octanoate) from the system and replaces it with non-metallic boronic acid catalysts, thereby eliminating the adverse effects on battery performance while maintaining polymerization productivity
Solution Approach 2:
The patent employs catalysts that can be easily removed or decomposed after reaction, such as boronic acids that form water-soluble complexes with lithium salts, allowing complete removal from the final polymer product without compromising battery reliability
3Productivity
If conventional synthesis routes are used, then polycarbonates can be produced, but ionic conductivity and electrochemical stability are limited
Solution Approach 1:
The patent changes the chemical structure parameters of the polycarbonate by using specific cyclic carbonate monomers and boronic acid-catalyzed polymerization to produce polymers with enhanced ionic conductivity and electrochemical stability while maintaining production efficiency
Solution Approach 2:
The patent produces composite polycarbonate structures with controlled molecular weight and architecture that combine the benefits of high production rate with superior ionic conductivity and electrochemical stability for lithium battery applications
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 method enables the production of polycarbonates with improved ionic conductivity, electrochemical stability, and mechanical strength, suitable for a wide temperature range, making them suitable for high-energy density batteries with high-potential electrodes.
Implementation Method 1
ring-opening (co)polymerization (ROP), catalyzed by methanesulfonic acid (MSA)
Data Source
Figure 1~2
Figure 3~4
Figure 5a~6b
AI summary
The invention relates to a process for preparing an electrolyte comprising at least the following steps: (i) synthesis of at least one (co)polymer by ring-opening (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, said (co)polymerization reaction being catalyzed by methanesulfonic acid and initiated, or not, by at least one compound comprising one or more hydroxyl function(s); (ii) protection of the hydroxyl functions at the chain ends of said (co)polymer(s); (iii) purification of said (co)polymer(s); (iv) mixing, in the presence or absence of a solvent medium, of said purified (co)polymer(s), obtained at the end of step (ii) or (iii), with at least one alkali or alkaline earth metal salt, in particular a lithium salt; and (v) formation of a solid electrolyte from said mixture.It also concerns the solid electrolyte thus obtained; and its use in an electrochemical system, in particular in a lithium battery.