Effect of Intermediate-Range Structure on Negative Electrode Properties of Wadsley–Roth Phase Ti₂Nb₁₀O₂₉

This study focused on Wadsley–Roth phase Ti₂Nb₁₀O₂₉ as a negative electrode material for lithium-ion batteries. We investigated the effect of a network consisting of corner-sharing octahedra, which form a conduction pathway for Li⁺, on the electrode properties. Charge/ discharge cycle tests show that the capacity of Ti₂Nb₁₀O₂₉ is significantly reduced by ball milling. Because the treatment broadens the Bragg peaks in the diffraction pattern, the poor electrode properties of the ball-milled sample are considered to be due to the disordered atomic configuration. To investigate the structural disorder in more detail, we performed total scattering and X-ray absorption fine structure measurements and analyzed the intermediate-range structure. The results reveal that ball milling significantly disrupts the octahedral network, indicating a disordered conduction pathway for Li⁺. It is also demonstrated that the subsequent heat treatment after ball milling alleviates the disorder in the intermediate-range structure and improves the electrode properties.