Oxide-Coated High-Nickel Cathode Material for Lower Impedance
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Solution Overview
Problem
Current lithium-ion battery positive electrode materials, such as lithium iron phosphate and low-nickel ternary materials, fail to meet the energy density requirements for motive power batteries due to inherent limitations, leading to deteriorated cycle performance and increased side reactions with the electrolyte, which hampers commercial mass production.
Innovation Solution
A high-nickel ternary positive electrode material with a substrate having a molecular formula LixNiyCozMkMepOrAm, coated with an oxide layer containing elements like Al, Ba, or Ti, is developed to control powder resistivity, reduce residual lithium, and mitigate polarization, thereby enhancing cycle and rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-nickel content is used in ternary positive electrode material to increase energy density, then the energy density of batteries is improved, but direct side reactions between the positive electrode active material and electrolytic solution are escalated drastically, and cycle performance is deteriorated drastically
Solution Approach 1:
The patent applies composite materials by combining high-nickel ternary material (LiNixCoyMn1-x-yO2 where 0.80<x≤0.95) with a protective coating layer comprising metal oxide (such as Al2O3, TiO2, ZrO2) and/or metal phosphate (such as AlPO4, TiPO4, ZrPO4). This composite structure allows the high-nickel substrate to provide high energy density while the coating layer provides stability and reduces side reactions, thereby improving cycle performance without sacrificing energy density.
Solution Approach 2:
The patent uses a coating layer as an intermediary between the high-nickel positive electrode active material and the electrolytic solution. This coating layer acts as a protective barrier that prevents direct contact and harmful side reactions between the high-nickel material and the electrolyte, while still allowing lithium ion transport. The coating layer comprises metal oxide and/or metal phosphate, forming an intermediate protective interface that resolves the contradiction between high energy density and cycle stability.
2Use of energy by moving object
If high-nickel content is used in ternary positive electrode material to increase energy density, then the energy density of batteries is improved, but side reactions between the positive electrode active material and electrolytic solution are escalated drastically
Solution Approach 1:
The patent uses a coating layer as an intermediary between the high-nickel positive electrode active material and the electrolytic solution. This coating layer acts as a protective barrier that prevents direct contact and harmful side reactions between the high-nickel material and the electrolyte, while still allowing lithium ion transport. The coating layer comprises metal oxide and/or metal phosphate, forming an intermediate protective interface that resolves the contradiction between high energy density and cycle stability.
Solution Approach 2:
The patent converts the harmful high reactivity of high-nickel material into a benefit by using it as the substrate for a protective coating layer. The high-nickel material provides high theoretical capacity and energy density, while the coating layer (metal oxide/phosphate) converts the harmful surface reactivity into a beneficial protective interface that stabilizes the material and reduces side reactions, thereby benefiting from both high capacity and stability.
3Quantity of substance
If the surface area of positive electrode active material is increased to improve capacity, then the capacity is improved, but the amount of residual lithium on the surface increases, leading to increased gassing and polarization
Solution Approach 1:
The patent applies composite materials by combining high-nickel ternary material (LiNixCoyMn1-x-yO2 where 0.80<x≤0.95) with a protective coating layer comprising metal oxide (such as Al2O3, TiO2, ZrO2) and/or metal phosphate (such as AlPO4, TiPO4, ZrPO4). This composite structure allows the high-nickel substrate to provide high energy density while the coating layer provides stability and reduces side reactions, thereby improving cycle performance without sacrificing energy density.
Solution Approach 2:
The patent applies local quality by creating a coating layer with specific properties (metal oxide and/or metal phosphate) on the surface of the high-nickel positive electrode active material. This coating layer has different chemical and physical properties compared to the bulk material, providing localized protection at the surface where it contacts the electrolyte. The coating layer specifically addresses surface-related issues (residual lithium, gassing, polarization) while the bulk high-nickel material maintains high capacity, thus resolving the contradiction between capacity and surface stability.
Data Source
AI summary
The present application relates to the electrochemical field, and in particular, to a positive electrode material, and an electrochemical energy storage apparatus having thereof. The present application provides a positive electrode material, including a substrate. The substrate includes secondary particles containing primary particles. A surface of the substrate is coated with an oxide coating layer. The oxide coating layer comprises a coating element, and the coating element is selected from one or more of Al, Ba, Zn, Ti, Zr, Mg, W, Y, Si, Sn, B, Co, or P. The electrochemical energy storage apparatus comprises the foregoing positive electrode material.