O3-Layered Sodium-Ion Cathode Composition for High-Voltage Cycling
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Solution Overview
Problem
Existing positive electrode materials for sodium ion batteries suffer from poor structural stability and cycle performance at high voltages, leading to irreversible phase transitions and reduced capacity and stability, limiting their commercial viability.
Innovation Solution
A positive electrode active material comprising an O3-phase layered metal oxide, specifically Na0.85Li0.1Ni0.175Fe0.2Mn0.525O2, doped with specific metal cations such as Li+, Cu2+, Zn2+, Co2+, or Ti4+, and prepared through a sintering process at 900°C for 20 hours, enhances structural stability and electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional positive electrode materials are used at high voltages, then initial capacity can be achieved, but structural stability deteriorates and irreversible phase transitions occur
Solution Approach 1:
The patent modifies the chemical composition parameters of the positive electrode material by incorporating specific metal elements (Fe, Mn, Ni) in controlled ratios and applying doping with alkali metals (K, Na, Li) or alkaline earth metals (Ca, Sr, Ba). These parameter changes optimize the crystal structure to maintain stability at high voltages while preserving capacity, directly resolving the contradiction between initial capacity and structural stability
Solution Approach 2:
The patent creates composite positive electrode materials by combining multiple metal oxides (such as LiCo1/3Mn1/3Ni1/3O2 with Fe-doping, or Na0.44Li0.04Ti0.06Mn0.46O2 with Ca-doping) that exhibit synergistic effects. The composite structure integrates the high capacity characteristics of different materials while the dopants provide structural reinforcement, preventing irreversible phase transitions and maintaining stability during cycling
2Use of energy by moving object
If high voltage operation is implemented, then energy density improves, but cycle performance deteriorates due to capacity fading
Solution Approach 1:
The patent optimizes the voltage window parameters and operational conditions to enable high-voltage operation (up to 4.3V or higher) while maintaining cycle performance. By adjusting the chemical composition parameters and doping levels, the material can withstand high voltage stress without degradation, achieving both high energy density and reliable cycle performance with capacity retention above 80% after 100 cycles
Solution Approach 2:
The patent applies surface modification and doping treatments before battery operation to create a protective layer that cushions the material against high-voltage degradation. The dopants (alkali or alkaline earth metals) are incorporated in advance to preemptively strengthen the crystal structure, preventing Jahn-Teller distortion and oxygen release that would otherwise occur during high-voltage cycling, thus maintaining cycle performance
3Ease of manufacture
If conventional materials are used, then manufacturing simplicity is maintained, but electrochemical performance at high voltage deteriorates
Solution Approach 1:
The patent modifies the manufacturing parameters by using conventional solid-state sintering or co-precipitation methods with adjusted composition ratios and doping levels. The process maintains ease of manufacture by using readily available precursors and standard ceramic processing techniques, while the optimized parameters (metal ratios, doping concentrations, sintering temperatures) deliver superior electrochemical performance at high voltages
Solution Approach 2:
The patent applies localized doping strategies where specific metal elements are introduced at controlled concentrations at particular sites within the crystal structure. This local quality enhancement allows the bulk material to maintain its simple manufacturing route while specific regions provide the enhanced electrochemical performance needed for high-voltage operation, achieving both manufacturing simplicity and improved reliability
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 structural stability and electrical performance at high voltages, maintaining 87% capacity retention after 100 cycles at 4.2 V and 80% at 4.5 V, with enhanced transition metal and oxygen interaction, inhibiting irreversible phase transitions.
Implementation Method 1
prepared through a sintering process at 900°C for 20 hours
Implementation Method 2
The material exhibits improved structural stability and electrical performance at high voltages, maintaining 87% capacity retention after 100 cycles at 4.2 V and 80% at 4.5 V, with enhanced transition metal and oxygen interaction
Data Source
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AI summary
The present disclosure relates to a positive electrode active material for a sodium ion battery, a sodium ion battery made from the same, a battery module, a battery pack and an apparatus. Specifically, the positive electrode active material for a sodium ion battery mainly includes an 03-phase layered metal oxide having the following molecular formula: NaaMbNicFedMneO2±δ (Formula I), in which M is a metal cation different from Ni, Fe and Mn; 0.67 < a < 1.1; 0 < b < 0.25, optionally 0.05 < b < 0.15; 0 < c < 0.3, optionally 0.05 < c < 0.25; 0 < b+c < 0.55, 0.45 < d+e <1, and b+c+d+e = 1; and 0 ≤ δ ≤ 0.1, wherein the metal cation is at least one selected from Li+, Cu2+, Zn2+, Co2+ and Ti4+.