Pseudo-Jahn-Teller Effect-Regulated Structural Distortion in WNb₁₂O₃₃ Triggering Highly Stable and Fast-Charge...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Tungsten niobium oxide (WNb12O33) possesses a ReO3 shear structure suitable for high lithium storage capacity.
• Poor electron and ion transport hinders WNb12O33's potential as an anode material.
• Enhancing conductivity while preserving structural integrity is crucial for WNb12O33 anodes.

Purpose of the Study:

• To investigate the effect of Cu2+ doping on WNb12O33 structure and electrochemical properties.
• To improve the electronic conductivity and lithium-ion transport of WNb12O33.
• To evaluate the performance of Cu2+-doped WNb12O33 as a lithium-ion battery anode.

Main Methods:

• Synthesis of Cu2+-doped WNb12O33 via a local structural distortion regulation strategy.
• Characterization using X-ray diffraction (XRD) to analyze crystal structure.
• Density Functional Theory (DFT) calculations to study electronic structure and bonding.
• Electrochemical testing to assess lithium storage capacity, ion diffusion, rate capability, and cycling stability.

Main Results:

• XRD confirmed changes in crystal structure symmetry upon Cu2+ doping.
• DFT calculations revealed altered bandgap and Nb-O bond lengths, enhancing electronic conductivity and Li+ adsorption.
• Cu2+-doped WNb12O33 exhibited a high reversible specific capacity of 272.6 mAh g-1.
• Promoted Li+ diffusion coefficient to 5.26 × 10-12 cm2 s-1.
• Demonstrated remarkable structural stability with reversible single-phase transition during cycling.
• Achieved high-rate capacity (147.2 mAh g-1 at 10 A g-1) and excellent cycling performance (84.3% retention after 1000 cycles at 5 A g-1).

Conclusions:

• Pseudo-Jahn-Teller effect-driven doping strategy effectively regulates local structure in WNb12O33.
• Cu2+ doping significantly enhances electronic conductivity and lithium-ion transport in WNb12O33.
• Cu0.05WNb11.95O33 shows great promise as a high-performance anode material for rapid energy storage applications.
• This approach offers a new perspective for designing and customizing shear structures for energy storage.