P2-Type Sodium Cathode Material with Controlled XRD Ratios
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Solution Overview
Problem
Conventional positive electrode active materials with a P2-type structure have limitations in terms of reversible capacity.
Innovation Solution
A positive electrode active material comprising a Na-containing oxide with a P2-type structure, characterized by specific X-ray diffraction peak intensity ratios (I1/I2 ≤ 0.10 and I1/I3 ≤ 0.70) and a chemical composition Na a Mn x-p Ni y-q Co z-r M p+q+r O 2, where x + y + z = 1 and p + q + r < 0.17, is developed to enhance crystallinity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional P2-type structure positive electrode active materials are used, then the material structure is stable, but the reversible capacity is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the X-ray diffraction peak intensity ratios (I1/I2 ≤ 0.10 and I1/I3 ≤ 0.70) to optimize the crystal structure. This parameter control enables the material to achieve both structural stability and enhanced reversible capacity by creating a specific degree of disorder in the (102) plane that increases intercalation sites while maintaining overall structural integrity
2Manufacturing precision
If the X-ray diffraction peak intensity I1 is increased, then the crystallinity is improved, but the reversible capacity decreases
Solution Approach 1:
The patent applies local quality by creating a specific local structural characteristic where the (102) plane exhibits controlled disorder (low I1 intensity) while other planes maintain good crystallinity. This local structural modification in the (102) plane increases intercalation sites and reversible capacity without compromising the overall crystalline structure and stability
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 material exhibits improved reversible capacity and stability due to reduced crystallinity in the (102) plane and increased intercalation sites, leading to enhanced performance in sodium-ion secondary batteries.
Implementation Method 1
An X-ray diffraction pattern of the Na-containing oxide satisfies I1/I2 ≤ 0.10, the X-ray diffraction pattern of the Na-containing oxide satisfies I1/I3 ≤ 0.70, the I1 is an intensity of an X-ray diffraction peak originating from (102) plane of the P2-type structure
Data Source
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AI summary
Disclosed is a positive electrode active material having a P2-type structure and having a large reversible capacity. The positive electrode active material of the present disclosure comprises a Na-containing oxide. The Na-containing oxide has a P2-type structure. The Na-containing oxide at least comprises, as constituting elements, at least one element among Mn, Ni, and Co; Na; and O. An X-ray diffraction pattern of the Na-containing oxide satisfies I1/I2 ≤ 0.10. The X-ray diffraction pattern of the Na-containing oxide satisfies I1/I3 ≤ 0.70. The I1 is an X-ray diffraction peak intensity originating from (102) plane of the P2-type structure, the I2 is an X-ray diffraction peak intensity originating from (002) plane of the P2-type structure, and the I3 is an X-ray diffraction peak intensity originating from (100) plane of the P2-type structure.