Electrospinning oxygen-vacant TiNb24O62 nanowires simultaneously boosts electrons and ions transmission capacities toward superior lithium storage

Abstract

The intercalation pseudocapacitive anode material TiNbxOx+2.5x (x = 2,5,24) has attracted much attention owing to its high theoretical specific capacity (388–402 mAh g−1) and relatively safe working voltage. However, Ti4+/Nb5+ has a 3d/4d empty orbital that leads to a lower electronic conductivity, which limits its practical application. Therefore, reasonable design and adjustment of an effective electron/ion transfer path is the key to the realization of high-performance anode material, which is of great significance to improve the multiplier performance and cycle life for lithium-ion batteries. In this work, we employ a facile electrospinning and subsequent hydrogenation process to synthesize one-dimensional TiNb24O62 (H-TNO) nanowires with oxygen vacancies. The rapid Li+ diffusion path and high Li+ diffusion coefficient are achieved by nano engineering, besides, hydrogen treatment brings oxygen vacancy to improve the electronic conductivity, together with providing more Li+ active sites for TNO materials. As a result, the as-prepared H-TNO-1h (treatment with 1 h) electrode delivers a high reversible specific capacity (305.2 mAh g−1 at 0.1 A g−1), safer working voltage (~ 1.7 V vs. Li/Li +), high initial Coulombic efficiency (91.9%), excellent rate properties (180.5 mAh g−1 at 5 A g−1) and superior cycle stability, making it become one of the best choices in titanium niobium electrode material used for lithium-ion batteries.