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

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 Ti3C2Tx 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.