Modified Gel Electrolyte Separator for Conductivity Without Brittleness
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Solution Overview
Problem
Current gel polymer electrolytes for lithium-ion batteries have poor room-temperature conductivity and mechanical properties due to high crystallinity, which is reduced by adding inorganic fillers, leading to brittleness and production difficulties.
Innovation Solution
A modified gel electrolyte separator is prepared using a slurry with silica as a nano functional material, polyethylene oxide (PEO) as a high polymer, a modified high block copolymer as a dispersant, and an acrylic binder with dichloromethane as an organic solvent, optimizing the composition to enhance ionic conductivity, mechanical strength, and temperature resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inorganic fillers are added to reduce crystallinity and improve ionic conductivity, then ionic conductivity is improved, but mechanical properties deteriorate due to brittleness
Solution Approach 1:
The patent uses a composite material system combining gel polymer electrolyte with inorganic fillers (Al2O3, SiO2, TiO2) to create a material that maintains both improved ionic conductivity and acceptable mechanical properties. The composite structure allows the inorganic fillers to be dispersed within the polymer matrix, providing ion transport pathways while the polymer phase maintains flexibility and mechanical integrity.
2Reliability
If inorganic fillers are added to suppress crystallinity and improve ionic transference number, then ionic transference number is improved, but the gel electrolyte separator becomes brittle
Solution Approach 1:
The patent optimizes the composition parameters by controlling the weight ratio of inorganic fillers to polymer electrolyte, and adjusting the molecular weight and composition of the polymer matrix. These parameter changes allow suppression of crystallinity and improvement of ionic transference number while maintaining sufficient mechanical flexibility by preventing excessive brittleness.
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 modified gel electrolyte separator exhibits high-temperature heat resistance, flame retardancy, and improved mechanical and electrochemical properties, suitable for lithium-ion batteries with broad application prospects.
Implementation Method 1
The inorganic fillers can be divided into two categories: inert fillers and active fillers. Common inert fillers include Al2O3, SiO2, or TiO2, which do not directly participate in the ion transport but increase the number of free Lit and promote the rapid transport of Lit, thereby improving ionic conductivity.
Implementation Method 2
The active fillers refer to inorganic solid electrolytes, which could directly participate in ion transport and provide a lithium source, thereby further improving the ionic conductivity.
Implementation Method 3
The modified gel electrolyte separator is prepared through impregnation in a modifying slurry including, in weight fraction, a nano functional material: 2% to 12%; a high polymer: 2% to 1%;
Data Source
AI summary
Disclosed are a modified gel electrolyte separator, and a preparation method and use thereof, belonging to the technical field of novel battery separator materials. The modified gel electrolyte separator is prepared through impregnation in a modifying slurry including: in weight fraction, a nano functional material: 2% to 12%; a high polymer: 2% to 1%; a dispersant: 5% to 2%; a binder: 5% to 3%; and an organic solvent: 85% to 97%, wherein the nano functional material is silica; the high polymer is polyethylene oxide; the dispersant is a modified high block copolymer; the binder is an acrylic binder with N-methyl-2-pyrrolidone as a solvent; and the organic solvent is dichloromethane. The modified gel electrolyte separator shows high-temperature heat resistance, flame retardancy, and high ductility, as well as significantly improved mechanical and electrochemical properties, and exhibits broad application prospects in the preparation of lithium-ion batteries.