O3-Type Sodium Cathode Material for Air Stability and Fast Ion Diffusion
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Solution Overview
Problem
O3-type layered sodium ion batteries face challenges due to low energy density, poor rate capability, and sensitivity to air, which hinder their commercial development, despite efforts like doping with hetero elements, as existing solutions do not adequately address structural stability and ion diffusion.
Innovation Solution
A cathode material with the chemical formula NaM1-x-y-zNixFeyMnzO2 is developed, where M includes a first metal element with f electrons and a second metal element with d electrons, enhancing structural stability and ion diffusion through entangled electron orbital interactions, and a preparation method involving solid-phase sintering to improve electrochemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If O3-NaNi0.5Mn0.5O2 is used as cathode material, then high theoretical specific capacity and electrochemical activity are achieved, but complex irreversible phase change and slow kinetic problem occur resulting in quick fall in capacity and poor rate capability
Solution Approach 1:
The patent changes the compositional parameters by introducing multiple dopants (Co, Al, Ti) at specific ratios to modify the crystal structure and electronic properties of the cathode material, thereby improving kinetic performance while maintaining high capacity
Solution Approach 2:
The patent creates a composite doped material system NaNi0.5-3x/4Co0.5xAl0.5xTi0.5xO2 combining multiple elements with complementary properties: Co enhances electrochemical activity, Al stabilizes structure, and Ti improves conductivity, achieving synergistic effect that resolves the contradiction between capacity and rate capability
2Quantity of substance
If O3-NaNi0.5Mn0.5O2 is used as cathode material, then sufficient sodium and high electrochemical activity are provided, but the material is particularly sensitive to air and structure destruction occurs resulting in deteriorated electrochemical properties
Solution Approach 1:
The patent modifies the compositional parameters by replacing vulnerable Mn sites with more stable Co, Al, and Ti elements, changing the chemical stability parameters of the material to resist air degradation while preserving sodium storage capability
Solution Approach 2:
The patent constructs a multi-element composite structure where Co provides stability, Al enhances structural rigidity, and Ti improves chemical inertness, creating a synergistic protective effect against air and water that prevents structure destruction
3Reliability
If hetero element doping is performed to improve electrochemical properties, then capacity retention is enhanced, but the material remains sensitive to air and water causing structure failure
Solution Approach 1:
The patent merges three different doping strategies (Co-doping for activity, Al-doping for stability, Ti-doping for conductivity) into a single integrated doping system, where the combined effect simultaneously improves capacity retention and provides comprehensive protection against air and water degradation
4Ease of manufacture
If sodium ion batteries are developed to replace lithium ion batteries, then abundant resources and low costs are achieved, but lower energy density occurs due to higher relative molecular mass and larger ion radius
Solution Approach 1:
The patent changes the electrochemical parameters of the cathode material through multi-element doping, increasing the operating voltage and capacity to compensate for the lower energy density inherent in sodium ion systems, thereby improving overall energy storage performance
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 cathode material exhibits improved structural stability, enhanced ion diffusion, and increased energy and power density, effectively addressing the limitations of existing sodium ion batteries by synergistically improving electrochemical properties and reducing air sensitivity.
Implementation Method 1
the f electron orbital in M and the d electron orbital in Ni, Fe, and Mn are mutually entangled, properties of the cathode material are synergistically improved, so as to improve the structural stability of the material and to reduce the susceptibility of the material to air
Implementation Method 2
interaction of all elements in the material can be facilitated, so that ions can move away from original positions to generate vacancies. The generation of vacancy can increase the ion diffusion channel of sodium ions
Implementation Method 3
uniformly mixing a cathode precursor salt, a sodium salt, and an M metal salt in a proportion to form a mixture, and sintering the mixture in a solid phase to obtain a cathode material
Data Source
AI summary
The disclosure relates to the technical field of batteries, and discloses a cathode material and a preparation method thereof, a cathode plate and an O3-type layered sodium ion battery. The chemical formula of the cathode material is NaM1-x-y-zNixFeyMnzO2, wherein M comprises a first metal element, and the first metal element has at least one f electron orbital. Ni, Fe and Mn elements in the cathode material are elements containing a d electron orbital. By doping the element M, on the one hand, the f electron orbital and the d electron orbitals are mutually entangled, properties of the cathode material are synergistically improved, so that the structure and air stability of the material are improved; and on the other hand, interaction of all elements in the material can be facilitated, so that ions can move away from original positions to generate vacancies, ion diffusion channels of sodium ions are enlarged, and the rate capability of the material is improved. In addition, a redox reaction of oxygen atoms in anions in charging and discharging processes of the material can be excited, and thus the energy density and the power density of the material are improved.