SODm Catalyst in Lithium Anode Battery Electrolyte
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Solution Overview
Problem
Lithium ion batteries face capacity deterioration due to the generation of by-products during charging and discharging, which reduce the battery's capacity and thermal stability, especially when using nickel-based cathode active materials.
Innovation Solution
Incorporating a superoxide dismutase mimic catalyst (SODm) in the electrolyte to convert superoxide into Li2O2, forming a Li2O2 film at the cathode-electrolyte interface, which suppresses side reactions and inhibits the dissolution of transition metals, thereby improving charge and discharge characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If nickel-based cathode active materials are used to increase battery capacity, then the battery capacity and voltage are improved, but the structure becomes unstable and thermal stability deteriorates due to reaction with electrolyte
Solution Approach 1:
A coating layer comprising lithium fluoride (LiF) and lithium oxynitride (Li3-x-yO1-zNz) is introduced as an intermediary between the nickel-based cathode active material and the electrolyte. This coating layer acts as a protective barrier that prevents direct contact and harmful reactions between the nickel-based material and the electrolyte, thereby maintaining structural stability and thermal stability while preserving the high capacity characteristics of the nickel-based cathode material.
2Ease of manufacture
If over-lithiated oxide cathode materials are used to reduce cobalt content, then manufacturing cost is reduced, but by-products are generated during charging and discharging that cover the cathode surface and reduce battery capacity
Solution Approach 1:
The coating layer of lithium fluoride and lithium oxynitride is applied in advance to the surface of the over-lithiated oxide cathode material before the charging and discharging cycles begin. This preliminary coating prevents the generation and deposition of harmful by-products during subsequent cycling by blocking the interaction between the cathode material and the electrolyte, thereby preventing capacity deterioration while maintaining the cost advantage of reduced cobalt content.
3Use of energy by moving object
If nickel-based cathode materials are used to achieve high voltage operation, then energy density is improved, but thermal stability becomes vulnerable due to reaction with electrolytic solution
Solution Approach 1:
The coating layer comprising lithium fluoride and lithium oxynitride serves as a thermal and chemical barrier between the nickel-based cathode material and the electrolyte. This intermediary layer suppresses exothermic reactions and prevents thermal runaway by blocking the direct interaction between the high-voltage nickel-based material and the electrolyte, thereby maintaining thermal stability while preserving the high energy density characteristics.
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 use of SODm in the electrolyte enhances the battery's capacity and stability by reducing by-product formation and maintaining the cathode's layered structure, leading to improved charge-discharge cycle-life and energy efficiency.
Implementation Method 1
the superoxide dismutase mimic catalyst (SODm) may serve to convert a superoxide (O2⋅−) that is generated as the cathode is activated upon charging into Li2O2
Implementation Method 2
The Li2O2 film may serve to inhibit a transition metal generated from the cathode from being dissolved in the electrolyte
Implementation Method 3
The superoxide dismutase mimic catalyst may serve to suppress side reactions of the superoxide (O2⋅−) that are generated as the cathode is activated upon charging
Data Source
AI summary
Provided are a high-capacity secondary battery including a cathode including an over-lithiated oxide cathode material or a Ni-rich cathode material; a lithium anode (Li anode); and an electrolyte including a superoxide dismutase mimic catalyst (SODm).