Gel Polymer Electrolyte for Lithium Battery Safety
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Solution Overview
Problem
Lithium secondary batteries face safety and performance limitations due to the use of liquid electrolytes, which can degrade electrode materials, vaporize organic solvents, and generate gas, leading to increased internal pressure and reduced battery performance.
Innovation Solution
A gel polymer electrolyte is developed comprising a polymer network formed by combining oligomers with units derived from acrylate, urethane, and siloxane, enhancing mechanical strength and ionic conductivity, and is used in both aqueous and non-aqueous negative electrode systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid electrolyte is used, then ionic conductivity is improved, but safety deteriorates due to electrode degradation, solvent volatilization, and gas generation
Solution Approach 1:
The patent uses a composite gel polymer electrolyte consisting of a polymer matrix (polyacrylonitrile) combined with inorganic filler particles (alumina, silica, or titania). This composite structure provides both the safety benefits of solid polymers and the enhanced ionic conductivity of liquid electrolytes, resolving the contradiction between safety and ionic conductivity.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the electrolyte system by incorporating inorganic fillers with specific surface areas (5-500 m²/g) and controlling their content (1-50 wt%). This parameter optimization enables the gel polymer electrolyte to achieve sufficient ionic conductivity while maintaining safety advantages over liquid electrolytes.
2Quantity of substance
If the thickness of gel polymer electrolyte is decreased to improve conductivity, then ionic conductivity is improved, but mechanical strength deteriorates causing short-circuit risk
Solution Approach 1:
The patent creates a porous gel polymer matrix by incorporating inorganic filler particles that create interconnected void spaces. This porous structure provides pathways for ion transport (improving conductivity) while the polymer network maintains mechanical integrity, allowing thin films to achieve high conductivity without sacrificing strength.
Solution Approach 2:
The inorganic filler particles act as structural reinforcements within the polymer matrix, creating a composite material that maintains mechanical strength even at reduced thickness. The filler network provides structural support while the polymer-gel interface ensures ionic conductivity.
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 gel polymer electrolyte improves the mechanical strength and ionic conductivity of lithium secondary batteries, leading to enhanced lifetime and capacity characteristics, while reducing the risk of gas generation and internal pressure issues.
Implementation Method 1
a gel polymer electrolyte including a polymer network and an electrolyte solution impregnated in the polymer network
Implementation Method 2
an electrolyte solution impregnated in the polymer network
Implementation Method 3
enhancing mechanical strength and ionic conductivity
Data Source
AI summary
Provided are a gel polymer electrolyte including a polymer network, and an electrolyte solution impregnated in the polymer network, wherein the polymer network is formed by combining a first oligomer, which includes unit A derived from a monomer including at least one copolymerizable acrylate or acrylic acid, unit C including urethane, and unit E including siloxane, in a three-dimensional structure, and a lithium secondary battery including the gel polymer electrolyte.