Al-Y-W Coated Nickel Cathode Material for High-Voltage Cycle Life
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Solution Overview
Problem
The increasing demand for high-capacity, high-energy-density rechargeable lithium batteries is hindered by the scarcity and high cost of cobalt, and existing cobalt-free materials face challenges with structural stability, high-voltage side reactions, and reduced cycle-life under high-temperature conditions.
Innovation Solution
A positive electrode active material comprising lithium nickel-based composite oxide core particles coated with a layer of aluminum, yttrium, and tungsten, which enhances structural stability and reduces gas generation under high-voltage and high-temperature conditions, while minimizing cobalt content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cobalt-free lithium nickel-based composite oxide is used as positive electrode active material, then production cost is reduced and availability is improved, but structural stability and cycle-life deteriorate under high-voltage and high-temperature conditions
Solution Approach 1:
The patent applies composite materials by creating a core-shell structure where the core is lithium nickel-based composite oxide and the shell is a coating layer containing aluminum, yttrium, and tungsten. This composite structure allows the bulk material to be cobalt-free (reducing cost) while the coating layer provides structural stability and resistance to degradation (improving cycle-life). The coating layer acts as a protective barrier that prevents direct exposure of the nickel-based core to harsh electrolyte environments under high-voltage and high-temperature conditions.
Solution Approach 2:
The patent applies local quality by creating a coating layer with specific composition (aluminum, yttrium, and tungsten) only on the surface of the lithium nickel-based composite oxide particles. The core particles maintain their cobalt-free nickel-based composition for cost-effectiveness, while the surface coating provides localized protection against structural degradation. This spatial differentiation of material properties allows the bulk material to be economical while the surface provides the necessary stability for long cycle-life under high-voltage and high-temperature operation.
2Ease of manufacture
If cobalt content is reduced or eliminated, then production cost decreases and supply availability improves, but high-voltage side reactions increase and structural stability decreases
Solution Approach 1:
The patent applies the intermediary principle by introducing a coating layer containing aluminum, yttrium, and tungsten as a mediator between the lithium nickel-based composite oxide and the electrolyte. This coating layer acts as an intermediate barrier that prevents direct harmful interactions between the nickel-based material and the electrolyte under high-voltage conditions. The coating layer suppresses side reactions such as electrolyte decomposition and gas generation while allowing ionic transport, thus protecting the cobalt-free core material from degradation.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel-based composite oxide with a coating layer containing aluminum, yttrium, and tungsten. This composite structure allows the bulk material to be cobalt-free (reducing cost) while the coating layer provides resistance to high-voltage side reactions and structural degradation. The coating layer acts as a protective barrier that prevents direct exposure of the nickel-based core to harsh electrolyte environments under high-voltage conditions.
3Quantity of substance
If high-capacity lithium nickel-based composite oxide is used, then energy density increases, but gas generation increases under high-voltage and high-temperature conditions
Solution Approach 1:
The patent applies the intermediary principle by introducing a coating layer containing aluminum, yttrium, and tungsten as a mediator between the high-capacity lithium nickel-based composite oxide and the electrolyte. This coating layer acts as an intermediate barrier that suppresses gas-generating side reactions between the high-capacity nickel-based material and the electrolyte under high-voltage and high-temperature conditions, while maintaining ionic transport for high capacity utilization.
Solution Approach 2:
The patent applies the blessing in disguise principle by using the coating layer to convert the potentially harmful high reactivity of the lithium nickel-based composite oxide (which enables high capacity) into a beneficial feature. The coating layer prevents direct harmful reactions that would cause gas generation, while allowing the high-capacity material to function effectively. The high reactivity of the nickel-based core is thus harnessed for high capacity without the detrimental side effects.
Data Source
AI summary
Provided are a positive electrode active material, and a method of preparing the positive electrode active material, and a positive electrode including the positive electrode active material, and a rechargeable lithium battery including the positive electrode active material. The positive electrode active material comprises core particles including a lithium nickel-based composite oxide and a coating layer provided on the surfaces of the core particles, with the coating layer including aluminum, yttrium, and tungsten.