O-vacancy and PANI dual-modified titanium dioxide for fast sodium storage

Abstract

TiO₂ is a promising anode material for sodium ion (Na⁺) storage owing to its structural stability, high safety profile and abundant resource availability. However, its poor conductivity hinders further practical application. Herein, we designed an O-vacancy and polyaniline (PANI) dual-modified TiO₂ anode (TiO₂-OV@PANI) to enhance its performance for Na⁺ storage. The O-vacancy in TiO₂ modulated the electronic structure, favourable for absorbing more Na⁺ and enhancing the reaction kinetics. The protonated PANI modification maintained the structural stability of the anode material and further increased the electron transfer to improve the reaction kinetics. As a result, the as-prepared TiO₂-OV@PANI demonstrated stable cycling ability with a high discharge capacity of 175 mAh g⁻¹ after 160 cycles at 1 A g⁻¹ and a high rate performance of 144 mAh g⁻¹ at 2.5 A g⁻¹. Our strategy provides a good reference for adapting the O-vacancy and PANI dual modification to enhance the performance of the TiO₂ anode for Na⁺ storage.