TiBzO1-z Coated High-Nickel Cathode for Oxygen-Loss Stability
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Solution Overview
Problem
Cobalt-free high-nickel positive electrode materials suffer from poor cycling stability due to oxygen loss during the cycling process, which affects their performance in lithium ion batteries.
Innovation Solution
A cobalt-free high-nickel positive electrode material is developed, comprising a cobalt-free high-nickel matrix material coated with a TiBzO1-z layer. The chemical formula of the matrix material is Li m Ni x Mn y O 2, with specific ranges for m, x, and y, and the coating layer has a mass percentage of 0.2% to 0.5% of the matrix material. The material is prepared by mixing the matrix material with TiBzO1-z solid solution particles and calcining the mixture at temperatures between 300°C to 900°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cobalt element is removed to reduce cost, then manufacturing cost is reduced, but cycling stability deteriorates due to oxygen loss
Solution Approach 1:
The patent applies composite materials by combining cobalt-free high-nickel matrix material (Li m Ni x Mn y O 2) with a TiB z O 1-z coating layer. This composite structure maintains the cost advantage of cobalt-free materials while the TiB z O 1-z coating layer prevents oxygen loss and improves cycling stability, effectively resolving the contradiction between low cost and high reliability
Solution Approach 2:
The patent uses parameter changes by optimizing the stoichiometric ratios (0.2≤m≤0.8, 0.4≤x≤0.95, 0.05≤y≤0.6) and the coating layer composition (0.2≤z≤0.8) to achieve the desired balance between cost reduction and performance maintenance
2Quantity of substance
If high-nickel content is used to increase capacity, then energy density is improved, but oxygen loss increases leading to poor cycling performance
Solution Approach 1:
The patent applies local quality by creating a TiB z O 1-z coating layer on the surface of the high-nickel matrix material. This localized modification protects the high-nickel core from oxygen loss while maintaining the high capacity benefits, allowing the bulk material to retain high nickel content without suffering from the associated cycling degradation
Solution Approach 2:
The composite structure of high-nickel matrix material combined with TiB z O 1-z coating layer enables the system to achieve both high capacity (from high nickel content) and good cycling performance (from the protective coating that prevents oxygen loss)
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 cobalt-free high-nickel positive electrode material exhibits improved high-temperature cycling performance, capacity, and initial efficiency in lithium ion batteries, with enhanced acid resistance, wear resistance, and mechanical strength due to the TiBxO1-x coating layer.
Implementation Method 1
oxygen vacancies present in TiBxO1-x contribute to the de-intercalation of lithium ions and the effect of reducing oxygen loss during the high-temperature solid-phase reaction
Implementation Method 2
TiBxO1-x reduces a contact area of the cobalt-free high-nickel positive electrode material with an electrolyte, relieving the occurrence of side reactions
Implementation Method 3
oxygen vacancies present in TiBxO1-x contribute to the de-intercalation of lithium ions
Data Source
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AI summary
Provided in the present disclosure are a cobalt-free high-nickel positive electrode material, a preparation method therefor and use thereof. The cobalt-free high-nickel positive electrode material comprises a cobalt-free high-nickel matrix material and a coating layer coated on the cobalt-free high-nickel matrix material, wherein a chemical formula of the cobalt-free high-nickel matrix material is LimNixMnyO2, where 0.2≤m≤ 0.8, 0.4≤x≤0.95, and 0.05≤y≤0.6; and the coating layer is TiBzO1-z, where 0.2≤z≤0.8. The cobalt-free high-nickel positive electrode material obtained by means of modification using the coating layer TiBzO1-z has good acid resistance and wear resistance, high mechanical strength and excellent conductivity; and when the cobalt-free high-nickel positive electrode material is used for a lithium ion battery, the high-temperature cycling performance, capacity and initial efficiency of the lithium ion battery are greatly improved.