Layered Oxide Material for Sodium-Ion Battery Cathodes
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Solution Overview
Problem
Existing sodium-ion secondary batteries face challenges with low charge capacity, poor cycling performance, and high costs due to the use of expensive and toxic materials like nickel and cobalt, as well as instability issues with P2-type and O3-type layered oxide materials.
Innovation Solution
A layered oxide material with a general chemical formula Na x Cu i Fe j Mn k M y O 2+β, where M is a doped transition metal element, is developed, using a method such as solid-state reaction, spray drying, sol-gel process, or co-precipitation, incorporating copper, iron, and manganese, which are abundant and non-toxic, to enhance charge capacity and cycling stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If P2-type layered oxide material is used, then cycling stability is improved, but initial charge capacity is reduced due to low sodium content
Solution Approach 1:
The patent changes the chemical composition parameters by incorporating copper and iron elements into the layered oxide structure, forming Na 0.9 Cu 0.225 Fe 0.3 Mn 0.475 O 2. This compositional modification enables the material to achieve both high initial charge capacity (104 mAh/g) and excellent cycling stability (93% capacity retention after 100 cycles) by optimizing the sodium content and transition metal ratios.
Solution Approach 2:
The patent creates a composite material system combining multiple transition metals (copper, iron, manganese) in specific ratios within the layered oxide structure. This composite approach leverages the complementary properties of each element: copper enhances capacity, iron improves stability, and manganese provides structural framework, achieving synergistic effects that resolve the contradiction between capacity and stability.
2Quantity of substance
If O3-type layered oxide material is used, then initial charge capacity is improved due to high sodium content, but cycling performance deteriorates
Solution Approach 1:
The patent modifies the structural parameters by stabilizing the O3-type layered oxide structure through copper and iron doping, preventing the phase transitions and structural collapses that normally occur during cycling. The specific composition Na 0.9 Cu 0.225 Fe 0.3 Mn 0.475 O 2 maintains high sodium content for capacity while the dopants reinforce the crystal structure for stability.
3Quantity of substance
If nickel and cobalt are used to achieve high charge capacity, then charge capacity is improved, but cost increases and toxicity increases
Solution Approach 1:
The patent replaces expensive and toxic nickel and cobalt with abundant, non-toxic, and inexpensive elements (copper, iron, manganese). The resulting material Na 0.9 Cu 0.225 Fe 0.3 Mn 0.475 O 2 achieves comparable or superior charge capacity (104 mAh/g) while dramatically reducing cost and environmental harm, aligning with the principle of substituting valuable materials with cheaper alternatives.
Solution Approach 2:
The patent changes the elemental composition parameters by eliminating nickel and cobalt entirely and using alternative transition metals. This compositional substitution maintains electrochemical performance while removing the harmful aspects associated with nickel and cobalt, achieving a sustainable and economically viable battery material.
4Reliability
If nanonization and carbon coating are applied to improve kinetic performance, then electron conductivity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent changes the intrinsic material parameters by incorporating copper and iron elements that naturally enhance electron conductivity within the layered oxide structure. The composition Na 0.9 Cu 0.225 Fe 0.3 Mn 0.475 O 2 achieves good kinetic performance through its optimized chemical composition rather than requiring additional nanostructuring or carbon coating layers, simplifying the overall device architecture and manufacturing process.
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 sodium-ion batteries using this layered oxide material exhibit high initial charge capacity, excellent cycling performance, and safety, making them suitable for large-scale energy storage applications like solar and wind power generation and smart grid systems.
Implementation Method 1
the lithium ions are reversibly deintercalated from the positive and negative electrode active material repeatedly without destroying the material structure
Implementation Method 2
A layered oxide material with a general chemical formula Na x Cu i Fe j Mn k M y O 2+β, where M is a doped transition metal element, is developed, using a method such as solid-state reaction
Data Source
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AI summary
A layered oxide material, a preparation method, an electrode, a secondary battery and use are disclosed. The layered oxide material has a general chemical formula NaxCuiFejMnkMyO2+β, in which M is an element that is doped for replacing the transition metals; x, y, i, j, k, and β are respectively the molar ratios of respective elements, provided that x, y, i, j, k, and β satisfy the relations: y+i+j+k=1, and x+my+2i+3j+4k=2(2+β), where 0.8≤x≤1, 0<i≤0.3, 0<j≤0.5, 0<k≤0.5, -0.02≤β≤0.02, and m is the valence of M. The layered oxide material has a space group of R3m.