Nickel-Manganese Composite Oxyhydroxide Air Stability
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Solution Overview
Problem
Nickel-manganese composite hydroxides with high manganese content are unstable in air and prone to manganese segregation during coprecipitation, washing, and drying, leading to non-uniform lithium composite metal oxides with insufficient battery performance due to the formation of manganese oxide by-products.
Innovation Solution
A nickel-manganese composite oxyhydroxide with a specific chemical composition and structure, stable in air and resistant to manganese segregation, is produced using a method involving aqueous metal salt solutions, caustic soda, and oxidizing agents, which is then used to create a lithium-nickel-manganese composite oxide for improved battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a nickel-manganese composite hydroxide with high manganese content is used as a precursor, then the energy density of the battery is improved, but the composite hydroxide becomes unstable in air and manganese segregates during coprecipitation, washing, and drying steps
Solution Approach 1:
The patent changes the chemical composition parameters by introducing a specific ratio of nickel to manganese (Ni:Mn = 1:3 to 1:5) and controlling the oxidation state of manganese to +4. This parameter change transforms the unstable composite hydroxide into a stable oxyhydroxide structure that prevents manganese segregation while maintaining high energy density in the resulting lithium secondary battery.
2Ease of manufacture
If a nickel-manganese composite hydroxide is dried after coprecipitation, then the material is ready for further processing, but manganese oxide (Mn3O4) forms as a by-product and manganese segregation occurs
Solution Approach 1:
The patent performs preliminary oxidation during the coprecipitation process itself, oxidizing manganese to the +4 state before drying occurs. This preliminary action prevents manganese segregation and Mn3O4 formation during subsequent drying steps, ensuring composition uniformity is maintained throughout the manufacturing process.
3Productivity
If a composite hydroxide containing Mn3O4 by-product is fired with lithium compound, then the lithium composite metal oxide is produced, but the product has non-uniform composition and insufficient battery performance
Solution Approach 1:
The patent applies preliminary anti-action by preventing Mn3O4 formation during the coprecipitation and drying stages through controlled oxidation of manganese to the +4 state. This preliminary prevention eliminates the harmful by-product before it can affect the final firing process, ensuring uniform composition and reliable battery performance in the lithium composite metal oxide product.
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 stable nickel-manganese composite oxyhydroxide prevents manganese oxide formation, maintains high metal element dispersibility, and enhances the energy density and cycle stability of lithium secondary batteries when used as a cathode material.
Implementation Method 1
an oxidizing agent, which is an oxygen-containing gas or an aqueous hydrogen peroxide solution
Implementation Method 2
a nickel-manganese composite oxyhydroxide obtained by coprecipitating an aqueous metal salt solution containing nickel and manganese
Data Source
AI summary
A nickel-manganese composite oxyhydroxide which is stable in the air, in which manganese oxide (Mn3O4) will not form as a by-product during long term storage or at the time of drying, and which has high metal element dispersibility, its production method, and its use. A nickel-manganese composite oxyhydroxide having a chemical compositional formula represented by Ni(0.25+α)−xM1xMn(0.75−α)−yM2yOOH (wherein each of M1 and M2 which are independent of each other, is at least one member selected from the group consisting of Mg, Al, Ti, V, Cr, Fe, Co, Cu, Zn and Zr, 0≤x≤0.1, 0≤y≤0.25, and −0.025≤α≤0.025), and having a hexagonal cadmium hydroxide type crystal structure, its production method and its use.