Multi-Element Cathode Coating to Reduce Micro-Powder in Li-Ion Batteries
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Solution Overview
Problem
Lithium-ion batteries face limitations in endurance mileage, poor low-temperature performance, and safety due to the low energy density and cycle stability of cathode materials, particularly the ternary 622 material, which is also the most expensive and heaviest component.
Innovation Solution
A multi-element cathode material with a dot-like and/or island-like coating, specific particle size distribution, and controlled surface roughness and coverage, prepared through a method involving high-temperature sintering, acid solution rinsing, and controlled coating, to reduce micro-powders and enhance structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional cathode materials are used, then manufacturing cost and weight are reduced, but energy density and cycle stability are insufficient
Solution Approach 1:
The patent uses composite materials by combining multiple elements (Li, Ni, Co, Mn, Al, Ti, Zr, Hf) in the cathode material formula Li1+aNixMnymCozMbO2, where b represents additional elements. This multi-element composition creates a composite structure that achieves higher energy density (180-220 mAh/g) while maintaining reasonable weight, resolving the contradiction between improving energy density and controlling weight.
2Quantity of substance
If high energy density cathode materials are used, then battery capacity improves, but cycle stability deteriorates
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core (multi-element cathode material) provides high capacity, while the outer coating layer (formed by secondary sintering at 200-1000°C) provides structural stability and protection. The coating coverage is controlled at 3-30% with specific roughness (20-200 nm), creating different functional zones that simultaneously achieve high capacity and good cycle stability.
3Productivity
If conventional sintering methods are used, then production efficiency is maintained, but micro-powder content increases reducing performance
Solution Approach 1:
The patent applies preliminary action by performing a first high-temperature sintering (700-1200°C) to form the base cathode material structure, then coarsely crushing and acid-rinsing to remove micro-powders before a second sintering step. This preliminary removal of micro-powders (reducing them to ≤5% by mass) before final processing improves particle quality and reduces subsequent processing requirements, maintaining production efficiency while achieving precise micro-powder control.
4Quantity of substance
If cathode material energy density is improved, then vehicle weight and price are reduced, but surface quality deteriorates affecting performance
Solution Approach 1:
The patent applies parameter changes by controlling the second sintering temperature (200-1000°C) and duration (2-24 hours) to transform the surface morphology. This secondary thermal treatment modifies surface parameters including roughness (20-200 nm) and coating coverage (3-30%), creating an optimized surface quality that complements the high energy density bulk material, thereby resolving the contradiction between energy density improvement and surface quality maintenance.
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 multi-element cathode material improves lithium-ion battery capacity and cycle performance by minimizing micro-powders, ensuring better slurry dispersibility and electrolyte utilization, leading to enhanced electrical performance and reduced material costs.
Implementation Method 1
A surface of the multi-element cathode material includes a dot-like coating and/or an island-like coating
Implementation Method 2
performing first high-temperature sintering on the mixture, to obtain a multi-element cathode material process product 1
Implementation Method 3
performing second high-temperature sintering and sieving on the mixture, to obtain the multi-element cathode material
Implementation Method 4
sequentially performing acid solution rinsing, water rinsing, and drying on the coarsely crushed multi-element cathode material process product 1
Data Source
AI summary
The present application relates to the technical field of lithium-ion battery and discloses a multi-element cathode material and, a preparation method thereof, and a lithium-ion battery. A surface of the multi-element cathode material includes a dot-like coating and/or an island-like coating. A particle diameter D1 with 1% cumulative particle size distribution of the multi-element cathode material is greater than or equal to 0.7 μm. An arithmetic average roughness Ra, measured with a three-dimensional scanning electron microscope, of the coating of the multi-element cathode material satisfies 20 nm≤Ra≤200 nm. A coverage Q of the dot-like coating and/or the island-like coating of the multi-element cathode material satisfies 3%≤Q≤30%. The surface of the multi-element cathode material contains the dot-like coating and/or the island-like coating, and the coating has specific arithmetic average roughness and coverage. Moreover, the multi-element cathode material has a relatively great particle size distribution D1.