Air Battery Electrolyte Layering to Prevent Acid Decomposition
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Solution Overview
Problem
Conventional lithium-air batteries face issues with discharge products precipitating as solid matter, which plug pores and poison the catalyst, reducing capacity and cycle performance, while using polyprotic carboxylic acids for improved solubility leads to decomposition and limited cycle performance.
Innovation Solution
Incorporating an aqueous electrolyte with a polyprotic acid having two or more carboxyl groups and a proton conduction layer to suppress discharge product precipitation and decomposition, allowing high solubility and improved cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If polyprotic carboxylic acid is used in the electrolyte to improve solubility of discharge products, then discharge capacity increases, but the acid decomposes on the air electrode and cycle performance deteriorates
Solution Approach 1:
The battery is divided into two distinct electrolyte layers: a non-aqueous electrolyte layer in contact with the air electrode and an aqueous electrolyte layer containing the polyprotic acid. This segmentation allows each layer to perform its specialized function without interference, resolving the contradiction between capacity improvement and cycle performance maintenance.
Solution Approach 2:
A proton-conducting membrane is introduced as an intermediary between the two electrolyte layers. This membrane selectively transports protons while preventing direct contact between the polyprotic acid and the air electrode, thereby preventing decomposition while maintaining the capacity benefits of the acid.
2Quantity of substance
If conventional aqueous electrolyte is used, then discharge products have limited solubility and precipitate as solid matter, but using polyprotic acid causes decomposition
Solution Approach 1:
The electrolyte system is segmented into two separate layers with distinct chemical properties. The aqueous layer contains the polyprotic acid to enhance solubility, while the non-aqueous layer prevents acid decomposition at the air electrode interface.
Solution Approach 2:
The proton-conducting membrane acts as an intermediary that enables the system to utilize the high solubility benefits of polyprotic acid while blocking the harmful decomposition reaction through selective proton transport.
3Quantity of substance
If solid discharge products precipitate in the electrolyte, then solubility limit is reached, but pores become plugged and catalyst is poisoned
Solution Approach 1:
The chemical parameters of the electrolyte are changed by introducing polyprotic acid, which increases the solubility of discharge products and prevents precipitation that would lead to pore plugging and catalyst poisoning.
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 solution enhances discharge capacity to nearly double and maintains excellent cycle performance by preventing polyprotic acid decomposition and precipitation of discharge products, thereby increasing energy density.
Implementation Method 1
a proton conduction layer positioned between the aqueous electrolyte layer and the air electrode
Implementation Method 2
The aqueous electrolyte layer includes an aqueous electrolyte including a polyprotic acid having two or more carboxyl groups
Implementation Method 3
An air battery, which uses oxygen in the air as a positive electrode active material
Data Source
AI summary
According to one embodiment, provided is an air battery including a negative electrode, an air electrode to which oxygen is supplied, a solid electrolyte layer positioned between the negative electrode and the air electrode, an aqueous electrolyte layer positioned between the solid electrolyte layer and the air electrode, and a proton conduction layer positioned between the aqueous electrolyte layer and the air electrode. The aqueous electrolyte layer includes an aqueous electrolyte including a polyprotic acid having two or more carboxyl groups, an electrolyte salt, and water.