Interlayer-Expanded MoS₂ Nanoflowers Vertically Aligned on MXene@Dual-Phased TiO₂ as High-Performance Anode for Sodium-Ion Batteries

Abstract

As a promising energy-storage and conversion anode material for high-power sodium-ion batteries operated at room temperature, the practical application of layered molybdenum disulfide (MoS₂) is hindered by volumetric expansion during cycling. To address this issue, a rational design of MoS₂ with enlarged lattice spacing aligned vertically on hierarchically porous Ti₃C₂T_<i>x</i> MXene nanosheets with partially oxidized rutile and anatase dual-phased TiO₂ (MoS₂@MXene@D-TiO₂) composites via one-step hydrothermal method without following anneal process is reported. This unique "plane-to-surface" structure accomplishes hindering MoS₂ from aggregating and restacking, enabling sufficient electrode/electrolyte interaction simultaneously. Meanwhile, the heterogeneous structure among dual-phased TiO₂, MoS₂, and MXene could constitute a built-in electric field, promoting high Na⁺ transportation. As a result, the as-constructed 3D MoS₂@MXene@D-TiO₂ heterostructure delivers admirable high-rate reversible capacity (359.6 mAh g^-1 up to 5 A g^-1) at room temperature, excellent cycling stability (about 200 mAh g^-1) at a low temperature of -30 °C, and superior electrochemical performance in Na⁺ full batteries by coupling with a Na₃V₂(PO₄)₃ cathode. This ingenious design is clean and facile to inspire the potential of advanced low-dimensional heterogeneous structure electrode materials in the application of high-performance sodium-ion batteries.