Doped Lithium Transition Metal Oxide for Low-Gas Cathode Additives
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Solution Overview
Problem
Existing lithium secondary batteries face challenges in increasing capacity and efficiency due to irreversible reactions and gas generation during charging and discharging, particularly with over-lithiated positive electrode materials like Li6CoO4, which can lead to pressure buildup and safety risks.
Innovation Solution
A lithium transition metal oxide, represented by Li6Co1-x-yZnxMyO4, is introduced with hetero-elements such as Al, Zn, or other transition metals to stabilize the crystal phase, minimizing side reactions and gas generation by suppressing oxidative properties of Co4+ cations, thereby enhancing safety and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If over-lithiated positive electrode material (Li6CoO4) is used to compensate for lithium loss in the negative electrode, then lithium loss is reduced, but gas generation increases causing pressure buildup and safety risks
Solution Approach 1:
The patent modifies the chemical composition parameters of the positive electrode material by introducing hetero-elements (Mg, Al, Ti, Zr, Nb) to replace some Co4+ cations. This changes the electrochemical properties to reduce gas-generating side reactions while maintaining lithium release capability. The specific composition ratios (0.01 ≤ x ≤ 0.50 for hetero-element content) are optimized parameters to balance lithium compensation and gas suppression.
Solution Approach 2:
The patent creates a composite positive electrode material combining Li6CoO4 with hetero-element dopants (Mg, Al, Ti, Zr, Nb). This composite structure maintains the high-capacity lithium release properties of Li6CoO4 while the hetero-elements suppress unwanted side reactions with the electrolyte, reducing gas generation. The composite material integrates multiple functional properties in a single electrode component.
2Quantity of substance
If Li6CoO4 is used as sacrificial positive electrode material, then initial capacity is improved, but crystal phase instability occurs leading to continuous gas generation
Solution Approach 1:
The patent stabilizes the crystal phase by introducing hetero-elements that modify the lattice structure parameters. The dopants (Mg2+, Al3+, Ti4+, Zr4+, Nb5+) have different ionic radii and charges compared to Co4+, which stabilizes the spinel structure and prevents Jahn-Teller distortion. This maintains the crystal phase stability while preserving the high initial capacity needed for lithium compensation.
3Quantity of substance
If high-capacity negative electrode material (metal or metal oxide) is used to increase battery capacity, then capacity increases, but volume change during charging/discharging increases making it difficult to achieve 15% or more content
Solution Approach 1:
The patent applies preliminary anti-action by using the Li6CoO4-based positive electrode material to pre-compensate for lithium loss that would otherwise occur during negative electrode formation. This preliminary lithium compensation prevents the need for excessive metal oxide content in the negative electrode, thereby reducing volume expansion issues while still achieving high capacity.
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 stabilized lithium transition metal oxide suppresses gas generation and maintains excellent battery performance by stabilizing the crystal phase, improving safety and extending the lifespan of lithium secondary batteries.
Implementation Method 1
minimizing side reactions and gas generation by suppressing oxidative properties of Co4+ cations
Data Source
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AI summary
The present disclosure relates to a lithium transition metal oxide, a positive electrode additive for a lithium secondary battery, and a lithium secondary battery including the same. According to the present disclosure, there is provided a lithium transition metal oxide capable of minimizing a side reaction with an electrolyte, thereby suppressing the generation of gas during charging and discharging of a lithium secondary battery.