Composite Electrode for Lithium Air Battery Using Ionic Liquid
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Solution Overview
Problem
Lithium air batteries face challenges in achieving high energy density due to the use of liquid electrolytes, which increase the battery's weight and react with discharge products, leading to reduced life and capacity characteristics.
Innovation Solution
A composite electrode is developed using a polymerization product of heteroatom-containing ionic liquids or a mixture of such ionic liquids and polymer ionic liquids, which forms a stable solid or gel phase electrolyte, reducing reactivity with discharge products and allowing for improved energy density and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a liquid electrolyte is used to fill the pores of the positive electrode, then the battery can operate, but the total weight of the cells increases, reducing energy density
Solution Approach 1:
The patent changes the physical state of the electrolyte from liquid to solid by using a polymerized ionic liquid. This parameter change eliminates the need to fill pores with heavy liquid electrolyte while maintaining ionic conductivity, thereby reducing cell weight and improving energy density.
Solution Approach 2:
The patent uses a composite structure consisting of a polymer matrix (from polymerized ionic liquid) that provides both structural support and ionic conductivity. This composite approach replaces the separate liquid electrolyte filling step with an integrated solid electrolyte layer, reducing overall weight.
2Weight of moving object
If existing solid electrolytes are used, then the electrolyte weight is reduced, but the solid electrolyte readily reacts with discharge products and decomposes at charge potential, reducing battery life
Solution Approach 1:
The patent modifies the chemical composition and physical properties of the solid electrolyte by polymerizing ionic liquids containing heteroatoms (N, O, P, or S). This creates a solid electrolyte with enhanced chemical stability toward discharge products like lithium peroxide and improved electrochemical stability at charge potentials, thereby extending battery life.
Solution Approach 2:
The patent develops a solid electrolyte that is stable enough to withstand multiple charge-discharge cycles without decomposing or reacting with discharge products. This replaces the need for frequent electrolyte replacement or battery recharging that would be required with unstable solid electrolytes.
3Weight of moving object
If a polymerized ionic liquid is used as solid electrolyte, then energy density improves and weight decreases, but the electrolyte must maintain chemical and electrochemical stability
Solution Approach 1:
The patent creates a composite solid electrolyte system where polymerized ionic liquids with specific heteroatom content provide both the desired weight reduction and enhanced stability. The heteroatoms (N, O, P, S) contribute to both mechanical properties and chemical stability, achieving a balance between weight reduction and stability requirements.
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 composite electrode enhances the energy density and life characteristics of lithium air batteries by providing a chemically and electrochemically stable environment, reducing the weight of electrolytes and minimizing reactions with discharge products like lithium peroxide.
Implementation Method 1
a polymerization product of a first heteroatom-containing ionic liquid
Implementation Method 2
the existing solid electrolytes readily react with a discharge product of the lithium air battery, the solid electrolyte is decomposed at a charge potential
Implementation Method 3
providing a chemically and electrochemically stable environment, reducing the weight of electrolytes and minimizing reactions with discharge products
Data Source
AI summary
A composite electrode for a lithium air battery including: i) a polymerization product of a first heteroatom-containing ionic liquid or ii) a mixture of a second heteroatom-containing ionic liquid and a polymer ionic liquid represented by Formula 1: