Lithium Manganese Oxide Cathode Pillar Element Stabilization
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Solution Overview
Problem
Lithium manganese-based oxides with a layered structure face issues of structural instability, phase transition during charging and discharging, rapid capacity reduction, and deteriorated lifespan characteristics, especially when stored at high temperatures, limiting their use in electric vehicle batteries due to manganese elution and low capacity per unit weight compared to lithium cobalt or nickel composite oxides.
Innovation Solution
A lithium manganese-based oxide with a layered crystal structure, where the transition metal layer or oxygen layer is substituted or doped with a pillar element such as vanadium, sodium, barium, strontium, zirconium, or calcium, enhancing structural stability and preventing manganese elution, thereby improving safety and lifespan characteristics by maintaining flat voltage sections during high-voltage charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium manganese composite oxides with a layered structure are used to complement low capacity problems of spinel, then capacity is improved, but structural stability deteriorates causing phase transition and rapid capacity reduction
Solution Approach 1:
The patent uses a composite material approach by combining lithium manganese oxide with a layered structure with pillar elements (such as Li, Na, K, Rb, Cs, Ag, or their combinations) that act as structural supports. This composite structure maintains the high capacity benefits of the layered lithium manganese oxide while the pillar elements prevent structural collapse and phase transitions, thereby resolving the contradiction between capacity and structural stability.
Solution Approach 2:
The patent changes the structural parameters of the lithium manganese oxide by introducing pillar elements at specific positions within the layered structure. This modification alters the physical and chemical properties of the material, enhancing structural stability without significantly compromising capacity. The pillar elements create a more robust framework that resists phase transitions during charging and discharging cycles.
2Quantity of substance
If lithium manganese composite oxides with a layered structure are used, then capacity is improved, but lifespan characteristics deteriorate due to unstable structure and phase transition
Solution Approach 1:
By creating a composite structure with pillar elements embedded in the layered lithium manganese oxide, the patent enhances both capacity and lifespan. The pillar elements act as structural reinforcements that prevent degradation mechanisms such as phase transitions and structural collapses, thereby extending the operational lifespan while maintaining high capacity throughout the battery's service life.
Solution Approach 2:
The pillar elements serve as a preventive measure against structural degradation. By incorporating these stabilizing elements before the battery undergoes charging and discharging cycles, the patent cushions against potential structural failures and phase transitions, thereby preserving both capacity and lifespan characteristics over extended periods.
3Stability of the object's composition
If lithium manganese composite oxides with a layered structure are stored at high temperature, then structural stability is maintained, but manganese elution occurs causing battery characteristic deterioration
Solution Approach 1:
The composite structure with pillar elements creates a more stable framework that reduces manganese elution at high temperatures. The pillar elements strengthen the crystal structure and reduce the mobility of manganese ions, thereby preventing their release into the electrolyte even under high-temperature storage conditions, while maintaining structural stability.
4Ease of manufacture
If lithium manganese composite oxides are used instead of lithium cobalt composite oxides, then cost and safety are improved, but capacity per unit weight is reduced
Solution Approach 1:
By creating a composite layered structure with pillar elements, the patent enhances the capacity per unit weight of lithium manganese oxide, making it more competitive with lithium cobalt oxide while maintaining the cost and safety advantages. The optimized structure allows for higher lithium content and better utilization of manganese, thereby increasing specific 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 use of pillar elements in the lithium manganese-based oxide cathode active material enhances structural stability, prevents capacity reduction, and improves lifespan characteristics, making it suitable for high-temperature storage and increasing capacity per unit weight, addressing the limitations of existing lithium manganese composite oxides.
Implementation Method 1
a transition metal layer including Mn and/or an oxygen layer are substituted or doped with a pillar element
Implementation Method 2
the lithium manganese-based oxide exhibits flat level section characteristics in which release of oxygen occurs together with lithium deintercalation during first charging in a high voltage range of 4.4 V or higher
Data Source
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AI summary
Disclosed is a lithium manganese (Mn)-based oxide including Mn as an essential transition metal and having a layered crystal structure, in which the amount of Mn is greater than that of other transition metal(s), the lithium manganese-based oxide exhibits flat level section characteristics in which release of oxygen occurs together with lithium deintercalation during first charging in a high voltage range of 4.4 V or higher, and at least one of a transition metal layer including Mn and an oxygen layer is substituted or doped with a pillar element.