Sodium-Ion Cathode Composition for Cu-Rich Layered Oxide Stability
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Solution Overview
Problem
The scarcity of lithium resources and rising prices have necessitated the development of sodium-ion batteries, but existing layered sodium-ion positive electrode active materials face challenges with cycling stability and specific capacity due to CuO impurity phases and low Cu amounts in the lattice.
Innovation Solution
A positive electrode active material with a specific composition, NaxMnaCubM1cM2dM3eO2+f−gRg, is formulated to facilitate Cu incorporation into the lattice, reducing CuO impurity phases and enhancing cycling stability and specific capacity by adjusting component proportions and incorporating elements like Mn, Ti, and Zr to stabilize the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If copper is added to improve specific capacity, then CuO impurity phases increase and cycling stability deteriorates
Solution Approach 1:
Alkali metal elements (Li, Na, K, Rb, Cs) are introduced as intermediary elements to mediate between copper addition and CuO impurity formation. These intermediary elements occupy specific sites in the layered oxide structure and regulate the chemical environment, preventing copper oxidation while maintaining high copper content for enhanced capacity
Solution Approach 2:
The invention changes the chemical composition parameters by precisely controlling the content ratios of copper and alkali metal elements. By adjusting these compositional parameters within specific ranges, the patent achieves optimal balance between capacity enhancement and structural stability, preventing CuO impurity formation
2Quantity of substance
If layered oxide structure is used for high capacity, then structural stability deteriorates due to lattice oxygen release
Solution Approach 1:
The patent creates a composite layered oxide structure containing multiple elements (copper, alkali metals, and other transition metals) working synergistically. This composite structure combines the high capacity benefits of copper with the structural stabilization effects of alkali metals, preventing lattice oxygen release while maintaining high specific capacity
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 improves cycling stability and specific capacity of sodium-ion batteries by stabilizing the layered oxide structure and reducing CuO impurity phases, while allowing more Cu to enter the lattice, thereby enhancing electrochemical performance.
Implementation Method 1
the incorporation of more copper into a crystal lattice of the positive electrode active material can be facilitated
Implementation Method 2
cycling stability of the positive electrode active material can be improved
Data Source
AI summary
A positive electrode active material and a preparation method thereof, a positive electrode plate, a battery, and an electric apparatus are provided. The positive electrode active material includes: NaxMnaCubM1cM2dM3eO2+f−gRg, where M1 includes an element capable of forming a cation with a valence of +2 or less, M2 includes an element capable of forming a cation with a valence of +3, M3 includes an element capable of forming a cation with a valence of +4 or higher, R includes a Group VIIA element, 0.67≤x≤1.2, a+b+c+d+e=1, a>0, b>0, c≥0, d≥0, e≥0, −0.1≤f≤0.1, 0≤g≤0.05, andb2×(b+c)2×(b+d)a×(a+e)4≤0.04.(I)