Lithium-ion diffusion path of tetragonal tungsten bronze (TTB) phase Nb₁₈W₁₆O₉₃

By taking tetragonal tungsten bronze (TTB) phase Nb₁₈W₁₆O₉₃ as an example, an improved solid-state sintering method at lower temperature of 1000 °C for 36 h was proposed via applying nanoscale raw materials. XRD, SEM and XPS confirm that the expected sample was produced. GITT results show that the lithium-ion diffusion coefficient of Nb₁₈W₁₆O₉₃ (10^—12 cm²/s) is higher than that of the conventional titanium-based anode, ensuring a relatively superior electrochemical performance. The lithium-ion diffusion mechanism was thoroughly revealed by using density functional theory simulation. There are three diffusion paths in TTB phase, among which the interlayer diffusion with the smallest diffusion barrier (0.46 eV) has more advantages than other typical anodes (such as graphite, 0.56 eV). The relatively smaller lithium-ion diffusion barrier makes TTB phase Nb₁₈W₁₆O₉₃ become a potential high- specific-power anode material.