Lithium Transition Metal Composite Oxide with Internal Dopants
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Solution Overview
Problem
Non-aqueous electrolyte secondary batteries using existing positive electrode active materials face reduced battery capacity due to side reactions and difficulty in lithium ion mobility, despite improved durability from surface coatings.
Innovation Solution
Incorporating elements like Ca, Sr, Sc, Er, Y, and W inside secondary particles of lithium-transition metal composite oxides facilitates lithium ion mobility, enhancing both durability and battery capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a surface coating is applied to the positive electrode active material, then durability is improved, but battery capacity decreases
Solution Approach 1:
The patent applies local quality by creating a dual-structure positive electrode active material where the internal core region maintains high lithium content (x ≥ 0.97 in LixNi0.8Co0.1Mn0.1O2) for high capacity, while the external surface region contains stabilized low-lithium composition or coating layers for durability. This spatial differentiation of composition and properties resolves the contradiction between capacity and durability.
Solution Approach 2:
The patent employs composite materials by combining multiple phases within the positive electrode active material structure - a core region of high-capacity lithium-rich spinel phase surrounded by a shell of stabilized lower-lithium phase or protective coating. This composite structure allows the inner core to provide high capacity while the outer shell provides stability and durability during cycling.
2Quantity of substance
If lithium content is increased to improve energy density, then battery capacity increases, but side reactions with electrolyte increase
Solution Approach 1:
The patent segments the positive electrode active material into distinct internal and external regions with different compositions. The internal core contains high lithium content (x ≥ 0.97) for high capacity, while the external surface contains stabilized composition with lower lithium content or protective coatings. This segmentation isolates the high-capacity core from direct contact with electrolyte, reducing side reactions while maintaining high battery capacity.
Solution Approach 2:
The patent introduces an intermediary layer (stabilized surface region or coating) between the high-lithium core material and the electrolyte. This intermediary protects the high-capacity core from direct side reactions with the electrolyte, allowing the battery to achieve high capacity without the harmful effects of increased side reactions.
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
This approach improves the durability and battery capacity of non-aqueous electrolyte secondary batteries by allowing better lithium ion movement, addressing the limitations of existing materials.
Implementation Method 1
a positive electrode active material for a non-aqueous electrolyte secondary battery includes a lithium-transition metal composite oxide capable of occluding and releasing Li
Data Source
AI summary
This positive electrode active material for a non-aqueous electrolyte secondary battery contains a lithium transition metal complex oxide capable of occluding and releasing Li. The lithium transition metal complex oxide is represented by general formula LixM1yOzFw (in the formula, 0.5 ≤×< 3.1, 1 ≤ y ≤ 2, 2 ≤ z+w ≤ 4, and M1 is at least one element selected from Ni, Co, Mn, Ti, Fe, Al, Ge, Si, and Nb), and M2 (M2 being at least one element selected from Ca, Sr, Sc, Er, Y, Zr, and W) is included in the interior of secondary particles of the lithium transition metal complex oxide.