Mn-Containing Powder for Sodium Battery Positive Electrode
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Solution Overview
Problem
Conventional positive electrode active materials for secondary batteries, particularly those used in sodium secondary batteries, face challenges due to strong cohesion between particles, making them difficult to disintegrate and requiring sieving, which reduces yield and exacerbates supply concerns.
Innovation Solution
A powder for positive electrode active material with Mn-containing particles, where 90 vol% of particles are in the range of 0.6 μm to 6 μm, and the powder is composed of carbonate, hydroxide, or a mixture thereof, produced through a method involving emulsion formation and calcination with a sodium compound, reducing the need for sieving and enhancing battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional powder for positive electrode active material is used, then the positive electrode active material can be obtained through calcination, but the particles exhibit strong cohesion and cannot be easily disintegrated, requiring sieving which reduces yield
Solution Approach 1:
The invention changes the particle size parameters of the raw material powder to resolve the contradiction. Specifically, it controls D50 (median particle diameter) to be in the range of 0.1-10 μm and ensures that 90 vol% or more of particles fall within 0.3-3 times D50. This parameter optimization prevents excessive particle aggregation during calcination while ensuring complete reaction, thereby eliminating the need for sieving and improving yield without compromising ease of manufacture
Solution Approach 2:
The invention performs preliminary particle size control on the raw material powder before calcination. By pre-adjusting the particle size distribution to meet specific criteria (D50 range and 90 vol% distribution), the material is prepared in advance to achieve optimal disintegration characteristics after calcination, avoiding the need for post-calcination sieving and improving overall productivity
2Productivity
If conventional powder is used, then the positive electrode active material can be produced, but sieving is required which increases processing complexity and time
Solution Approach 1:
The invention performs preliminary particle size control on the raw material powder before calcination. By pre-adjusting the particle size distribution to meet specific criteria (D50 range and 90 vol% distribution), the material is prepared in advance to achieve optimal disintegration characteristics after calcination, avoiding the need for post-calcination sieving and improving overall productivity
Solution Approach 2:
The invention changes the particle size parameters of the raw material powder to resolve the contradiction. Specifically, it controls D50 (median particle diameter) to be in the range of 0.1-10 μm and ensures that 90 vol% or more of particles fall within 0.3-3 times D50. This parameter optimization prevents excessive particle aggregation during calcination while ensuring complete reaction, thereby eliminating the need for sieving and improving yield without compromising ease of manufacture
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 a positive electrode active material that can be easily used in sodium secondary batteries, reducing the requirement for sieving and addressing supply concerns, while enhancing battery characteristics such as capacity.
Implementation Method 1
the powder and a lithium compound are mixed and calcined, whereby a positive electrode active material is obtained
Data Source
AI summary
The present invention provides a positive electrode active material that can suppress the necessity of performing sieving and is suitable for use in secondary batteries, particularly sodium secondary batteries. Also provided is a powder for a positive electrode active material as a raw material for the positive electrode active material. The powder for a positive electrode active material of the present invention comprises Mn-containing particles. In the cumulative particle size distribution on the volume basis of particles constituting the powder, D50, which is the particle diameter at a 50% cumulation measured from the smallest particle, is in the range of from 0.1 μm to 10 μm, and 90 vol % or more of the particles constituting the powder are in the range of from 0.3 times to 3 times D50. The powder for a positive electrode active material comprises Mn-containing particles, and 90 vol % or more of the particles constituting the powder are in the range of from 0.6 μm to 6 μm. The positive electrode active material is a powdery positive electrode active material obtained by calcining a mixture of the powder for positive electrode active material and a sodium compound. The positive electrode for sodium rechargeable batteries comprises the positive electrode active material.