Metal Halide Electrode Ionic Liquid Electrolyte Reversibility
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Solution Overview
Problem
Conventional non-aqueous electrolyte secondary batteries using metal halides as electrode active materials face challenges with reaction reversibility, solubility issues, and self-discharge due to high solubility of metal halides in organic solvents, leading to poor charging/discharging performance.
Innovation Solution
Incorporating an ionic liquid with a cation having an alkoxyalkyl group as the solvent in the non-aqueous electrolyte, which enhances the solubility and electrochemical reactivity of alkali metal or alkaline earth metal halides, allowing for smoother reversible redox reactions of metal halides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal halide is used as electrode active material in conventional non-aqueous electrolyte secondary batteries, then energy density can be increased, but reaction reversibility deteriorates due to high solubility of metal halides in organic solvents
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing an ionic liquid component with specific functional groups (carboxylate, sulfate, sulfonate, or phosphate) into the non-aqueous electrolyte system. This parameter change modifies the solubility characteristics and electrochemical properties of the electrolyte, enabling it to simultaneously support high energy density metal halide electrodes while maintaining excellent reaction reversibility through reduced unwanted side reactions.
2Quantity of substance
If metal halide is used as electrode active material, then electrical capacity increases, but self-discharge increases due to high solubility in organic solvents
Solution Approach 1:
The patent modifies the electrolyte composition by incorporating an ionic liquid with specific functional groups that alter the solubility and stability parameters of metal halides. This parameter change reduces the self-discharge rate while preserving the high electrical capacity benefits of metal halide electrodes.
Solution Approach 2:
The ionic liquid component acts as an intermediary substance between the metal halide electrode and the conventional non-aqueous electrolyte. It mediates the interaction by providing a chemical environment that suppresses unwanted side reactions and self-discharge while maintaining the electrochemical activity necessary for high capacity.
3Productivity
If conventional non-aqueous electrolyte is used with metal halide electrode, then battery operation is possible, but charging/discharging performance deteriorates due to poor reaction reversibility
Solution Approach 1:
The patent creates a composite electrolyte system by combining conventional non-aqueous electrolyte components with an ionic liquid containing specific functional groups. This composite material approach integrates the benefits of both systems: the operational characteristics of conventional electrolytes with the enhanced reversibility and stability provided by the ionic liquid component.
Solution Approach 2:
The patent optimizes the composition parameters of the electrolyte by controlling the concentration and type of ionic liquid additive, thereby improving charging/discharging performance while maintaining battery operability.
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
This approach improves the reaction reversibility and reduces self-discharge, enabling a non-aqueous electrolyte secondary battery with enhanced energy density and reliability by facilitating the movement of halogen ions in and out of the electrode active material.
Implementation Method 1
the non-aqueous electrolyte contains, as a solvent, an ionic liquid of which a component is a cation having an alkoxyalkyl group
Implementation Method 2
a reversible redox reaction of the metal halide, which is the electrode active material, proceeds smoothly
Implementation Method 3
enabling a non-aqueous electrolyte secondary battery with enhanced energy density and reliability by facilitating the movement of halogen ions in and out of the electrode active material
Data Source
AI summary
The present application provides an electrochemical energy storage device with a desirable reaction reversibility by using a metal halide as an electrode active material. The electrochemical energy storage device disclosed herein includes: a positive electrode; a negative electrode; and a non-aqueous electrolyte in contact with the positive electrode and the negative electrode, wherein: at least one of the positive electrode and the negative electrode contains a metal halide as an electrode active material; and the non-aqueous electrolyte contains, as a solvent, an ionic liquid of which a component is a cation having an alkoxyalkyl group.