Alkaline Battery Positive Electrode Material Stabilization
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Solution Overview
Problem
Alkaline storage batteries face limitations in increasing the number of reaction electrons and discharge capacity due to low conductivity of Ni(OH)2 and instability of α-Ni(OH)2 in alkaline media, despite efforts to enhance Ni use efficiency and phase stabilization.
Innovation Solution
Incorporating a Sr compound, Ca compound, or lanthanide elements like Y and Lu into nickel hydroxide, with Al or Ga in solid solution, to stabilize α-phase and β-phase nickel hydroxide, thereby increasing the number of reaction electrons and discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If Al is dissolved in solid solution in nickel hydroxide to stabilize α-phase, then the stability of α-Ni(OH)2 is improved, but the conductivity of the positive active material deteriorates
Solution Approach 1:
The patent combines nickel hydroxide with cobalt oxyhydroxide coating and multiple dopant elements (Al, Ga, Y, lanthanides, Sr, Ca) to create a composite material structure. The CoOOH coating layer compensates for the low conductivity of Ni(OH)2 while the dopants stabilize the α-phase, achieving both stability improvement and conductivity maintenance through material composition design.
Solution Approach 2:
The patent optimizes the concentration parameters of dopant elements in nickel hydroxide. Specifically, Al or Ga is held in solid solution at 5-16 mol%, Y or lanthanide elements are present at 0.25-6 mass%, and Sr or Ca compounds are included at controlled amounts. These parameter optimizations balance phase stabilization with conductivity preservation.
2Stability of the object's composition
If the content of A element (Al or Ga) in solid solution is increased to stabilize α-phase, then the stability of nickel hydroxide is improved, but the tap density of the material deteriorates
Solution Approach 1:
The patent identifies an optimal parameter range for A element content at 5-16 mol% in solid solution. This optimized concentration provides sufficient α-phase stabilization while minimizing the negative impact on tap density, representing a balanced parameter optimization rather than extreme values.
Solution Approach 2:
The patent creates a composite structure with multiple functional components: A element (Al/Ga) for phase stabilization, Y/lanthanide elements for enhancing reaction electrons, and Sr/Ca compounds for additional stabilization. This multi-component composite achieves phase stability with reduced adverse effects on physical properties like tap density compared to single-dopant systems.
3Quantity of substance
If Y or lanthanide elements are added to increase the number of reaction electrons, then the discharge capacity is improved, but the complexity of the positive electrode material increases
Solution Approach 1:
The patent merges multiple functional elements into a single integrated positive electrode material system. Y or lanthanide elements (0.25-6 mass%), A elements (5-16 mol%), and Sr/Ca compounds are combined in one material formulation, allowing simultaneous achievement of phase stabilization, conductivity improvement, and enhanced reaction electron capacity without requiring separate components.
Solution Approach 2:
The positive electrode material is designed with multi-functionality: the A element (Al/Ga) provides phase stabilization, Y/lanthanide elements enhance the number of reaction electrons, and Sr/Ca compounds provide additional stabilization. This universal material design achieves multiple objectives within a single electrode composition, reducing overall system complexity.
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 incorporation of these elements significantly enhances the number of reaction electrons and discharge capacity, with optimal results achieved when Al or Ga is in 5-16 mol% solid solution and lanthanide content is 0.25-6 mass%, particularly with Y, Sm to Lu, and Ca or Sr compounds, improving tap density and oxygen generation potential.
Implementation Method 1
an A element as at least one element selected from the group consisting of Al, and Ga is held in solid solution in a crystallite of the nickel hydroxide
Data Source
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AI summary
A positive electrode material for an alkaline storage battery includes: nickel hydroxide; and at least one of a Sr compound, a Ca compound, and a compound of at least one element selected from the group consisting of Y and lanthanide elements of atomic number 62 (Sm) to 71 (Lu). An A element which is at least one element selected from the group consisting of Al, Ga, Mn, and Mo is held in solid solution in a crystallite of the nickel hydroxide. The content of the A element, [A]/([Ni] + [A]), is 5% or more and 16% or less (where [A] represents the molarity of the A element in the crystallite and [Ni] represents the molarity of Ni). The nickel hydroxide includes α-phase nickel hydroxide and β-phase nickel hydroxide. In this positive electrode material, the number of reaction electrons is large and moreover the capacity per volume is large.