Layered Copper Oxide Cathode for Sodium-Ion Battery Energy Density
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Solution Overview
Problem
Current sodium-ion batteries face limitations in energy density and stability due to the scarcity and toxicity of vanadium resources, as well as the instability and low capacity of existing cathode materials, particularly the P2-phase oxides, which restrict their practical application in large-scale energy storage systems.
Innovation Solution
A layered copper-containing oxide material with a general chemical formula Na0.68+a Ni b Cu c M d Mn e O2+δ is developed, featuring a simple preparation process and abundant raw materials, which is applied as a positive electrode active material in sodium-ion secondary batteries, providing high working voltage, initial Coulombic efficiency, and cycling stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If vanadium-based cathode materials (Na3V2(PO4)3, Na3V2(PO4)2F3) are used to achieve high voltage and capacity, then energy density is improved, but resource scarcity and toxicity increase costs and environmental harm
Solution Approach 1:
The patent changes the chemical composition parameters by substituting vanadium with copper and adjusting the Na/Mn/Ni/Cu ratios to achieve high-voltage stability without toxic vanadium. The general formula Na0.68+aNibCucMdMneO2+δ allows systematic parameter optimization to maintain energy density while eliminating harmful elements.
Solution Approach 2:
The patent replaces expensive and toxic vanadium-based materials with cheaper, abundant copper-containing materials. The copper-based cathode provides comparable performance at lower cost and without the environmental toxicity associated with vanadium extraction and processing.
2Quantity of substance
If P2-phase oxide materials are used to achieve large capacity, then capacity is improved, but air stability deteriorates
Solution Approach 1:
The patent creates a composite cathode material combining multiple elements (Na, Mn, Ni, Cu) in a layered P2-phase structure. This composite approach leverages the high capacity of P2-phase oxides while the specific Cu-containing composition provides enhanced air stability compared to conventional P2-phase materials.
Solution Approach 2:
The patent introduces copper at specific compositional positions within the layered oxide structure to locally enhance stability. The general formula Na0.68+aNibCucMdMneO2+δ allows copper to occupy specific transition metal sites, providing localized stabilization that preserves overall air stability while maintaining high capacity.
3Use of energy by moving object
If lithium-ion batteries are used to achieve high specific energy, then energy efficiency is improved, but resource cost increases
Solution Approach 1:
The patent replaces lithium-ion technology with sodium-ion technology, substituting expensive and geographically concentrated lithium resources with abundant, cheap sodium resources. The copper-containing cathode material enables sodium-ion batteries to achieve competitive specific energy without the high resource costs of lithium.
Solution Approach 2:
The patent changes the electrochemical system parameters by transitioning from lithium to sodium ions and optimizing the cathode composition (Na0.68+aNibCucMdMneO2+δ) to achieve high voltage and capacity. This parameter change enables cost-effective large-scale energy storage while maintaining high specific energy performance.
Data Source
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AI summary
The present invention discloses a layered copper-containing oxide material and a preparation process and purpose thereof. The material has a general chemical formula of Na0.68+aNibCucMdMncO2+δ, where Ni, Cu, M, and Mn respectively form octahedral structures together with six oxygen atoms that are most adjacent thereto, the octahedral structures have arrangements with common edges and constitute transition metal layers; alkali metal ions Na+ are located between every two of the transition metal layers; M is specifically one or more of Mg2+, Mn2+, Zn2+, Co2+, Al3+, B3+, Cr3+, Mn3+, Co3+, V3+, Zr4+, Ti4+, Sn4+, Mo4+, Ru4+, Nb4+, Sb5+, Nb5+, Mo6+, and Te6+; and a, b, c, d, e, δ, and m meet (0.68+a)+2(b+c)+md+4e=2(2+δ), and b+c+d+e=1.