Pulverulent Nickel Hydroxide Precursors for High-Density Battery Electrodes
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Solution Overview
Problem
Existing nickel-containing precursors for lithium mixed metal oxides and nickel hydroxides lack sufficient compressive strength and density, leading to inhomogeneous electrodes and reduced performance in lithium-ion and nickel-metal hydride batteries, as they tend to break during processing, affecting the electrode's density and electrochemical properties.
Innovation Solution
A pulverulent compound of the formula Ni b M1 c M2 d (O) x (OH) y (SO4) z with specific compositional ranges and a proprietary preparation process involving a reactor with a centrally inserted stirrer shaft and propellers arranged in different planes, ensuring high turbulence and homogeneous mixing, resulting in secondary particles with compressive strengths of at least 50 MPa and low porosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional nickel-containing precursors are used, then the processing is simpler, but the compressive strength is insufficient and particles break during processing
Solution Approach 1:
The patent changes the compositional parameters by introducing sulfate groups (SO4) with specific content ranges (0.001 ≤ z ≤ 0.03) and controlling the ratios of metal elements (Ni, Co, Mn, Al, Mg, Zn, Ca, Sr, Ba) to achieve optimal compressive strength. The sulfate modification transforms the physical and mechanical properties of the precursor particles without fundamentally changing the preparation approach
Solution Approach 2:
The patent creates a composite structure by combining nickel hydroxide with sulfate groups and multiple metal elements (Co, Mn, Al, Mg, Zn, Ca, Sr, Ba) in specific ratios. This composite approach enhances the compressive strength of the particles while maintaining their functional properties for battery applications
2Volume of stationary object
If high compression pressure is applied during electrode preparation, then the electrode density increases, but particles break and homogeneity deteriorates
Solution Approach 1:
The patent performs preliminary strengthening of particles by introducing sulfate groups and optimizing metal element composition before the electrode compression step. This preliminary action increases particle robustness, allowing them to withstand subsequent compression pressures without breaking, thus maintaining both high density and particle integrity
3Stability of the object's composition
If coprecipitated or coated nickel compounds are used as precursors, then homogeneous distribution of elements is achieved, but the compressive strength remains insufficient
Solution Approach 1:
The patent modifies the compositional parameters by introducing sulfate groups with controlled content (0.001 ≤ z ≤ 0.03) and optimizing the ratios of metal elements. This parameter change enhances compressive strength while preserving the homogeneous distribution achieved through coprecipitation or coating methods
4Quantity of substance
If particles are made denser to increase volumetric energy density, then the energy density improves, but the particles become more prone to breaking
Solution Approach 1:
The patent applies preliminary sulfate modification and compositional optimization to strengthen particles before they are subjected to density-increasing compression. This preliminary strengthening allows particles to achieve high density while maintaining sufficient strength to resist breaking during and after compression
Solution Approach 2:
The patent changes the chemical composition by introducing sulfate groups and optimizing metal element ratios, which simultaneously increases particle density and enhances mechanical strength. This dual effect resolves the contradiction between achieving high volumetric energy density and maintaining particle integrity
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 process produces nickel hydroxides with enhanced compressive strength, maintaining particle integrity during processing, achieving high electrode densities and improved electrochemical performance, including increased charging capacity and volume capacity in batteries.
Implementation Method 1
reaction of the starting material solutions in a highly turbulent reaction zone of the reactor in which the flows produced by the stirrer strike one another frontally
Implementation Method 2
filtration, washing and drying of the material
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The present invention relates to pulverulent compounds of the formula NibMlcM2d (0) x (OH)y (SO4) z, a process for the preparation thereof and the use thereof as precursors for the preparation of active materials for lithium secondary batteries.