A partially disordered crystallographic shear block structure as fast-charging negative electrode material for...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Well-ordered crystalline structures are vital for battery electrode performance, influencing ion diffusion kinetics.
• Niobium tungsten oxides with ReO3-type blocks show potential as fast-charging negative electrode materials.
• Structural disorder typically hinders conductivity, but its role in niobium tungsten oxides is explored here.

Purpose of the Study:

• To investigate the impact of structural disorder on the Li-ion storage performance of niobium tungsten oxides.
• To compare the performance of a partially disordered Nb12WO33 phase with its ordered monoclinic counterpart.
• To establish structure-property correlations for designing advanced battery materials.

Main Methods:

• Synthesis and characterization of a partially disordered Nb12WO33 phase.
• Electrochemical testing, including galvanostatic cycling at various rates (e.g., 20 C, 80 C).
• Analysis of structural stability and Li-ion migration pathways during electrochemical cycling.

Main Results:

• A novel, partially disordered Nb12WO33 structure featuring varied block sizes and distorted tetrahedra was identified.
• This disordered phase demonstrated significantly enhanced Li-ion storage performance compared to the ordered monoclinic phase.
• High capacity retention was observed at fast charge/discharge rates: 62.5% at 20 C and 44.7% at 80 C.
• The disordered structure proved robust during cycling with minimal local structural changes.

Conclusions:

• Introducing controlled disorder into niobium tungsten oxide shear structures can enhance fast-charging performance.
• The identified disordered Nb12WO33 structure facilitates accelerated Li-ion migration.
• This work provides valuable insights for designing high-performance negative electrode materials for advanced batteries.