Partly Oxidized Mixed Metal Hydroxide Cathode Precursor
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Solution Overview
Problem
Current lithium secondary battery technologies face challenges in achieving high tap density, cycle stability, thermal reliability, and cost-effectiveness for cathode materials, particularly in the synthesis of mixed metal oxides using nickel, cobalt, and manganese, which often result in inadequate particle shape and increased sodium content, affecting battery performance.
Innovation Solution
A chemical compound of the formula NibM1cM2d(O)x(OH)y is developed, where M1 includes elements like Fe, Co, and M2 includes Mn, Al, with specific ratios and oxidation levels, resulting in a partly oxidized mixed metal hydroxide with high tap density and low sodium content, avoiding gamma-oxyhydroxide structures, and an efficient process for its preparation is implemented, including co-precipitation and partial oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If higher concentrations of cobalt and manganese are used to improve electrochemical properties and thermal stability, then charging/discharging properties and thermal reliability are improved, but the spherical particle shape becomes difficult to maintain and manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the concentration ratios of metallic components (nickel, cobalt, manganese) in the co-precipitation process. Specifically, it maintains cobalt and manganese concentrations below 33 mol% each while optimizing the nickel content to preserve spherical particle shape. The invention also controls pH values (9-13) and oxidation states during synthesis to achieve the desired balance between thermal reliability and particle morphology.
Solution Approach 2:
The patent creates a composite mixed metal hydroxide material comprising nickel, cobalt, and manganese in specific ratios. This composite structure allows the material to benefit from the thermal stability provided by cobalt and manganese while nickel maintains the spherical particle shape. The composite nature of the precursor material enables simultaneous achievement of improved electrochemical properties and preserved particle morphology.
2Shape
If vigorous stirring is used during precipitation to achieve abrasion and spherical particles, then particle shape is improved, but average particle sizes are limited and manufacturing precision is reduced
Solution Approach 1:
The patent applies preliminary action by ensuring complete co-precipitation of all metallic components (nickel, cobalt, manganese) before any stirring or abrasion occurs. By pre-forming the composite hydroxide structure with correct stoichiometry and spherical morphology through controlled precipitation conditions (pH 9-13, appropriate metal ratios), the subsequent stirring process maintains rather than creates the spherical shape, preserving particle size precision while achieving the desired morphology.
3Quantity of substance
If co-precipitation is performed in inert gas atmosphere or with reducing agent to achieve high tap density, then volumetric energy density is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies self-service by utilizing the natural oxidation characteristics of the co-precipitation process to achieve high tap density without requiring inert gas atmospheres or additional reducing agents. The controlled co-precipitation of nickel, cobalt, and manganese hydroxides in aqueous solution naturally produces a dense, well-packed precursor structure. This self-organizing precipitation process eliminates the need for complex atmosphere control equipment while achieving the desired high volumetric energy density in the final battery material.
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 solution provides improved cycle stability, charging/discharging properties, and higher tap density, leading to better volumetric energy density and reduced sodium impurities, enhancing the quality and efficiency of lithium mixed metal oxides for secondary batteries.
Implementation Method 1
co-precipitation of spherical mixed metal hydroxides from corresponding metal salt solutions
Implementation Method 2
partial oxidation of the precipitation product (mixed metal hydroxide) using an oxidizing agent
Data Source
AI summary
The invention relates to a chemical compound of the formula NibM1cM2d(O)x(OH)y, wherein M1 denotes at least one element from the group consisting of Fe, Co, Mg, Zn, Cu and/or mixtures thereof, M2 denotes at least one element from the group consisting of Mn, Al, B, Ca, Cr and/or mixtures thereof, wherein b≤0.8, c≤0.5, d≤0.5, and x is a number between 0.1 and 0.8, y is a number between 1.2 and 1.9, and x+y=2. A process for the preparation thereof, and the use thereof as a precursor for the preparation of cathode material for secondary lithium batteries are described.