Lithium Multi-Metal Cathode Surface Modification via Calcination
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Solution Overview
Problem
Current lithium-ion batteries using ternary transition metal oxides as cathode materials face limitations in phase transformation, safety due to thermal instability, and capacity deterioration after repeated charge and discharge cycles, which are not adequately addressed by existing surface modification methods, particularly for industrial-scale applications.
Innovation Solution
A method involving the preparation of a cathode material by dissolving nickel, manganese, and cobalt salts in de-ionized water, forming a multi-element metal hydroxide suspension, adding a metal salt solution to precipitate a hydroxide, mixing with lithium salts, and calcinating under controlled oxygen conditions to produce lithium multi-metal composite oxide particles with a thin oxide film, optimizing particle size and composition for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface modification is applied to LiNixMnymCo1−x−yO2 cathode material, then thermal stability and cyclic performance are improved, but manufacturing complexity increases and cycle life remains insufficient for industrial applications
Solution Approach 1:
The patent applies preliminary action by forming a protective oxide layer on the cathode material surface through controlled calcination in an oxygen atmosphere before the material is put into service. The method involves mixing the cathode precursor with a lithium salt and calcining at 600-900°C in oxygen-containing atmosphere, which pre-forms a stable surface layer that prevents subsequent degradation during cycling, thereby improving cyclic performance without requiring complex post-processing steps
Solution Approach 2:
The patent employs parameter changes by optimizing the calcination temperature range (600-900°C) and oxygen atmosphere conditions to control the formation of surface oxide layer. By adjusting these parameters, the method achieves improved thermal stability and cyclic performance while maintaining manufacturing simplicity, as the surface modification is integrated into the existing calcination process rather than requiring separate treatment steps
2Power
If LiNixMnymCo1−x−yO2 is used as cathode material, then high power output is achieved, but phase transformation and thermal instability occur
Solution Approach 1:
The patent applies parameter changes by controlling the calcination temperature (600-900°C) and oxygen atmosphere to optimize the crystal structure and surface composition of the cathode material. This thermal treatment stabilizes the layered structure, prevents phase transformation during cycling, and maintains the high power output characteristics by preserving the electroactive surface areas
Solution Approach 2:
The patent employs composite materials by creating a core-shell structure where the inner core is LiNixMnymCo1−x−yO2 providing high power output, and the outer shell is a protective oxide layer formed during calcination that provides thermal stability and phase stability. This composite structure combines the advantages of both materials while mitigating their individual drawbacks
3Quantity of substance
If high nickel content is used in LiNixMnymCo1−x−yO2, then specific capacity increases, but safety issues due to thermal runaway reaction worsen
Solution Approach 1:
The patent converts the harmful effect of high nickel content (thermal runaway risk) into a benefit by using controlled calcination in oxygen atmosphere to form a stable oxide surface layer. This layer acts as a protective barrier that prevents thermal runaway reactions while preserving the high specific capacity of the nickel-rich cathode material, effectively transforming the safety hazard into a protective feature
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 method results in a cathode material with improved cycling durability, safety, and specific capacity, suitable for high-rate charge and discharge applications, with exceptional durability and safety characteristics, maintaining capacity retention over multiple cycles.
Implementation Method 1
dissolving a salt of nickel, a salt of manganese, and a salt of cobalt in de-ionized water to obtain an aqueous solution
Implementation Method 2
adding the aqueous solution into an alkaline solution to form a suspension of multi-element metal hydroxide particles
Implementation Method 3
adding a solution of a salt of a metal into the suspension to form a solid product comprising a precipitate of a hydroxide of the metal on the surface of the multi-element metal hydroxide particles
Implementation Method 4
calcinating the solid mixture under an atmosphere with an oxygen content higher than 21% at a temperature from about 600° C. to about 900° C. for a time period from about 4 hours to about 12 hours to obtain a calcinated product
Implementation Method 5
calcinating the solid mixture under an atmosphere with an oxygen content higher than 21%
Data Source
AI summary
Provided herein is a method for preparing a surface modified cathode material for lithium-ion battery, wherein the cathode material comprises lithium multi-metal composite oxide particles capped with a thin film of an oxide of the metal, wherein the lithium multi-metal composite oxide is represented by Li1+zNixMnyCo1−x−yO2; and wherein z is from 0 to 0.2; x is from 0.35 to 0.8; y is from 0.1 to 0.45; and the metal is one or more elements selected from the group consisting of Fe, Mn, Al, Mg, Zn, Ti, La, Ce, Sn, Zr, Ru and combination thereof. The cathode material disclosed herein exhibits a high initial specific capacity from 150 mAh/g to 200 mAh/g, possesses good safety characteristics and shows impressive energy retention of about 91% after 1000 cycles.