Sodium-Doped Lithium-Rich Cathode Material for Easier Li-Ion Extraction
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Solution Overview
Problem
Conventional lithium-rich metal oxide materials exhibit significant resistance to lithium-ion extraction during charging, leading to lower charging capacity and energy density in secondary batteries.
Innovation Solution
Doping a certain amount of sodium at lithium sites in the lithium-rich metal oxide material to expand the interlayer spacing in the crystal lattice, reducing the resistance to lithium-ion extraction and improving the effective utilization rate of lithium ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional lithium-rich metal oxide materials are used with high lithium-ion content, then the energy density of the battery is improved, but the resistance to lithium-ion extraction from the crystal lattice increases significantly
Solution Approach 1:
The patent applies local quality by doping sodium specifically at lithium sites within the crystal lattice structure. This creates localized regions with modified properties (larger ionic radius of Na+ compared to Li+) that expand the interlayer spacing locally, thereby reducing resistance to lithium-ion extraction in those specific areas while maintaining high overall lithium content for energy density.
Solution Approach 2:
The patent changes the physical parameter of interlayer spacing in the crystal lattice by introducing sodium ions. The substitution of Li+ with larger Na+ ions increases the d-spacing between layers, which directly reduces the resistance to lithium-ion extraction and improves charging capacity while maintaining high lithium content.
2Object-generated harmful factors
If the interlayer spacing in the crystal lattice is expanded by doping sodium, then the resistance to lithium-ion extraction is reduced, but the structural stability of the material may be compromised
Solution Approach 1:
The patent carefully controls the doping concentration parameter (x in Lim-xNaxMOy) to optimize the balance between expanding interlayer spacing and maintaining structural stability. By limiting sodium content to specific ranges (0.01≤x/m≤0.25), the patent achieves sufficient lattice expansion to reduce extraction resistance while preventing excessive distortion that would compromise crystal structure stability.
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 doping increases the charging capacity and energy density of the battery by facilitating easier lithium-ion extraction and diffusion, while reducing costs.
Implementation Method 1
Since the radius of sodium ions is larger than that of lithium ions, doping a certain amount of sodium at lithium sites facilitates the expansion of interlayer spacing in the crystal lattice of the material
Implementation Method 2
reducing the resistance to lithium-ion extraction from the crystal lattice, thereby increasing the charging capacity of the battery
Data Source
AI summary
The present application provides a sodium-doped lithium-rich metal oxide material and a preparation method thereof, a positive electrode material, a positive electrode plate, a battery, and an electric apparatus. The sodium-doped lithium-rich metal oxide material includes a compound Lim-xNaxMOy. The sodium-doped lithium-rich metal oxide material of the present application facilitates reducing the resistance to lithium-ion extraction from the crystal lattice, thereby increasing the charging capacity of the battery.