Oxide-Coated High-Nickel Cathode Material for Stable Cycling
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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 electrolytes as nickel content increases.
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 Zr, to reduce powder resistivity and residual lithium, mitigating polarization and side reactions, and 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 with electrolytic solution are escalated and cycle performance is deteriorated
Solution Approach 1:
An oxide coating layer comprising at least one of Al, Ba, Zn, Ti, Zr, Mg, W, Y, Si, Sn, B, Co, or P is applied on the surface of the substrate. This coating layer acts as an intermediary barrier between the high-nickel substrate and the electrolyte, preventing direct harmful reactions while allowing ion transport, thus resolving the contradiction between high energy density and cycle performance
Solution Approach 2:
The positive electrode material is designed as a composite structure combining a high-nickel ternary substrate (LiNixCoyMn1-x-yO2 where 0.80≤x≤0.98) with an oxide coating layer. This composite structure leverages the high capacity of nickel-rich materials while the oxide coating provides stability and resistance to electrolyte degradation, achieving both high energy density and improved cycle life
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 with electrolytic solution are escalated
Solution Approach 1:
The oxide coating layer serves as a protective intermediary that physically separates the high-nickel substrate from the electrolyte, preventing direct contact and harmful side reactions such as oxygen release and electrolyte decomposition, while maintaining ionic conductivity for battery operation
Solution Approach 2:
The coating process transforms the inherently reactive high-nickel surface, which causes harmful side reactions, into a beneficial structure where the oxide coating layer absorbs and protects against the reactive nature of nickel, converting the harmful reactivity into a controlled interface that enhances overall battery performance and stability
3Power
If powder resistivity is reduced to decrease direct current impedance, then rate performance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes multiple parameters including nickel content (0.80≤x≤0.98), coating element composition, and sintering conditions to achieve the target powder resistivity range. By systematically adjusting these parameters, the invention achieves low direct current impedance and high rate performance while maintaining feasible manufacturing precision through controlled synthesis processes
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.