Nitrogen-doped carbon decorated TiO2/Ti3C2T MXene composites as anode material for high-performance sodium-ion batteries

Titanium oxide (TiO2), which has favourable cycling stability and low preparation cost, suffers from low electrical conductivity in sodium-ion batteries (SIBs). Rational construction of nano-sized TiO2 and conductive materials is an efficient strategy to achieve enhanced electrochemical properties. Here, nitrogen-doped carbon decorated TiO2/Ti3C2Tx MXene (NC-TiO2/MXene) is synthesized by utilizing polyethyleneimine (PEI) and Ti3C2Tx MXene as precursors. As a result, a crumpled NC-TiO2/MXene composite is fabricated, where nano-TiO2 is dispersed on the surface of the crumpled MXene and all the elements (Ti, O, C, and N) are uniformly distributed. The large specific surface area and the stable construction of NC-TiO2/MXene can be beneficial for electrolyte infiltration and reversible Na ions storage. Through combining the advantages of well-dispersed TiO2 nanoparticles, the conductive MXene network and the improved electrochemical kinetics, the NC-TiO2/MXene electrolyte retains excellent cycling ability (157.5 mAh g−1 at 2 A g−1 after 1900 cycles) and rate performance (100.1 mAh g−1 at 10 A g−1) in SIBs. This work offered a rational construction of TiO2-based composites with enhanced electrochemical performance.