Aqueous Electrolyte Battery Using Mo Redox for High Capacity
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Solution Overview
Problem
Existing aqueous solution electrolyte secondary batteries face challenges with low capacity and limited potential window, which exceeds the theoretical decomposition voltage of water, making them impractical for use, and there is a need for a battery with a wider potential window and high capacity using an oxidation-reduction reaction of Mo3+/Mo6+.
Innovation Solution
An aqueous solution electrolyte secondary battery is designed with a positive electrode and negative electrode active material that reversibly occludes and releases lithium ions, utilizing a lithium salt dissolved in an aqueous solution that forms a room temperature molten hydrate, allowing a potential window exceeding 2.0 V, and incorporating a negative electrode active material that undergoes oxidation-reduction reactions of Mo3+/Mo6+, along with a complex oxide containing transition metals and trivalent Mo for high capacity and voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an aqueous solution electrolyte is used in a secondary battery, then safety and environmental friendliness are improved, but the potential window is limited by water decomposition voltage resulting in low capacity
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by using high concentration lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) aqueous solution, which shifts the potential window beyond the conventional water decomposition limit, enabling higher battery capacity while maintaining safety
Solution Approach 2:
The patent employs a composite electrolyte system combining lithium salt (LiTFSI) with aqueous solution, creating a unique electrolyte composition that extends the potential window to exceed 2.0 V, thereby resolving the contradiction between safety and capacity
2Quantity of substance
If the potential window exceeds 2.0 V, then battery capacity is improved, but water electrolysis occurs reducing efficiency
Solution Approach 1:
The patent modifies the electrolyte concentration parameter to high concentration LiTFSI aqueous solution, which suppresses water electrolysis even when operating potential window exceeds 2.0 V, thereby achieving high capacity without significant energy loss
Solution Approach 2:
The patent converts the potentially harmful water electrolysis into a beneficial outcome by using high concentration LiTFSI aqueous solution that suppresses electrolysis while enabling extended potential window operation, thus turning a limitation into an advantage
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 battery achieves a high capacity and voltage while inhibiting water electrolysis, providing a practical and efficient aqueous solution electrolyte secondary battery with a potential window exceeding 2.0 V, ensuring stability and safety.
Implementation Method 1
at least part of the aqueous solution electrolyte forms a room temperature molten hydrate
Implementation Method 2
forms a room temperature molten hydrate
Implementation Method 3
at least part of the Mo causes an oxidation-reduction reaction of Mo3+/Mo6+ through charging and discharging
Data Source
AI summary
An aqueous solution electrolyte secondary battery includes: a positive electrode including a positive electrode active material that reversibly occludes and releases lithium ions; a negative electrode including a negative electrode active material that reversibly occludes and releases lithium ions; and an aqueous solution electrolyte in which a lithium salt is dissolved. The negative electrode active material contains Mo, at least part of the Mo causes an oxidation-reduction reaction of Mo3+/Mo6+ through charging and discharging, and a potential window for charging and discharging exceeds 2.0 V.