NASICON Battery Material P-Site Doping for Higher Conductivity
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Solution Overview
Problem
NASICON-type battery materials suffer from poor electronic conductivity and low electrochemical activity due to their polyanionic structure, which limits their rate performance and ionic conductivity.
Innovation Solution
Doping the phosphorus site of NASICON-type battery materials with non-metallic elements having higher electronegativity, such as S and Se, improves electronic conductivity and rate performance by reducing the Coulomb effect and band gap value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If doping is applied to improve electrochemical performance, then electronic conductivity and rate performance improve, but the patent requires a novel doping scheme beyond conventional methods
Solution Approach 1:
The patent changes the doping parameter from conventional metal element doping to non-metallic element doping at the phosphorus site. This parameter change in the doping strategy fundamentally alters the electronic structure and bonding characteristics, achieving improved electrochemical performance through a novel approach rather than incremental improvements to existing doping methods.
Solution Approach 2:
The patent creates a composite doping system by combining non-metallic elements (S, Se) with the NASICON structure at the phosphorus site. This composite approach integrates elements with different electronegativities and bonding characteristics into the crystal lattice, producing synergistic effects that enhance both electronic conductivity and structural stability beyond what conventional single-element doping achieves.
2Reliability
If non-metallic elements with higher electronegativity are doped at the phosphorus site, then electronic conductivity improves, but the structural stability must be maintained
Solution Approach 1:
The patent utilizes parameter changes in electronegativity by selecting non-metallic elements (S, Se) with higher electronegativity than phosphorus. This electronegativity parameter change creates stronger M-O bonds that reduce the Coulomb effect between oxygen and alkali metal ions, thereby improving electronic conductivity while the controlled doping concentration (0<y≤1/3) maintains structural stability.
Solution Approach 2:
The patent applies local quality modification by doping non-metallic elements specifically at the phosphorus site rather than uniformly throughout the structure. This localized doping at the P-site creates specific electronic and bonding modifications in the PO4 tetrahedra regions, improving electronic conductivity where needed while preserving the overall NASICON framework 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 doping of non-metallic elements at the phosphorus site significantly enhances the electronic conductivity and rate performance of NASICON-type battery materials, leading to improved electrochemical kinetics and structural stability.
Implementation Method 1
the doping of the element M at the phosphorus site can reduce the band gap value of the compound A3V2-xEx(P1-yMyO4)3 and improve the electronic conductivity of the material
Implementation Method 2
after the doping element M substitutes some of the P atoms, the number of charges of O atoms originally connected to the element P can be reduced, thereby reducing the Coulomb effect between the O atoms and the A atoms
Data Source
AI summary
Battery materials and preparation methods therefor, and secondary batteries. The general molecular formula of a battery material may include A3V2-xEx(P1-yMyO4)3, wherein the element A represents an alkali metal element; the element E represents a doping element that substitutes for V, and comprises at least one of transition metal elements, rare earth elements, Mg and Sr; the element M represents a doping element that substitutes for P, and comprises at least one of S and Se; and 0≤x≤1, and 0<y≤⅓.