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

Abstract

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.

Keywords

• wadsley–roth phase
• intermediate-range structure
• total scattering
• pair distribution function