Solid Electrolyte Film Polymer Reduces Interfacial Resistance
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Solution Overview
Problem
Lithium-air batteries with liquid electrolytes face challenges due to increased cell weight and interfacial resistance issues between the positive electrode and the lithium-ion conducting medium, which hinder the development of high-energy density batteries.
Innovation Solution
A novel polymer compound with a specific repeating unit structure is used to create a solid electrolyte film that reduces interfacial resistance and enhances ionic conductivity, stability, and thermal stability, thereby improving the performance of lithium-air batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a liquid electrolyte is used in the lithium-air battery, then the ionic conductivity is improved, but the cell weight increases and energy density decreases
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid, and specifically develops a polymer electrolyte with glassy state at room temperature. This parameter change (from liquid to solid polymer electrolyte) maintains ionic conductivity while eliminating the weight penalty associated with liquid electrolytes filling electrode pores
Solution Approach 2:
The patent creates a composite polymer electrolyte system combining glassy polymer matrix with lithium salts. The composite structure integrates the mechanical stability of solid polymer with the ionic conductivity provided by lithium salts, achieving both low weight and high ionic conductivity
2Weight of moving object
If a solid electrolyte is used in the positive electrode, then the cell weight is reduced and energy density is improved, but the contact area between the solid electrolyte and lithium-ion conducting medium is reduced, resulting in increased interfacial resistance
Solution Approach 1:
The patent creates local quality variations in the polymer electrolyte by introducing side chains with different properties at specific positions. The side chains containing ether oxygens or carbonyl groups are locally concentrated at the interface regions, providing enhanced interaction with lithium ions and improving interfacial contact quality without compromising bulk properties
Solution Approach 2:
The patent employs a thin film structure for the polymer electrolyte with controlled thickness and flexible morphology. The thin film design increases the surface area to volume ratio, improving contact area with electrodes, while the flexible polymer chains adapt to the electrode surface topology, ensuring intimate contact and reducing interfacial resistance
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 solid electrolyte film with the polymer compound achieves improved ionic conductivity, reduced interfacial resistance, and enhanced stability, leading to better lithium-ion conductivity and extended battery lifetime.
Implementation Method 1
a lithium-ion conducting medium between the positive electrode and the negative electrode
Implementation Method 2
there is a need for a method of reducing interfacial resistance between a positive electrode and a lithium-ion conducting medium
Data Source
AI summary
A polymer compound including a repeating unit represented by Formula:wherein R1, R2, R3, R4, a1, a2, and a11 in Formula 1 are as defined in the specification.