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

Abstract

Titanium oxide (TiO 2 ), which has favourable cycling stability and low preparation cost, suffers from low electrical conductivity in sodium-ion batteries (SIBs). Rational construction of nano-sized TiO 2 and conductive materials is an efficient strategy to achieve enhanced electrochemical properties . Here, nitrogen-doped carbon decorated TiO 2 /Ti 3 C 2 T x MXene (NC-TiO 2 /MXene) is synthesized by utilizing polyethyleneimine (PEI) and Ti 3 C 2 T x MXene as precursors. As a result, a crumpled NC-TiO 2 /MXene composite is fabricated, where nano-TiO 2 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-TiO 2 /MXene can be beneficial for electrolyte infiltration and reversible Na ions storage. Through combining the advantages of well-dispersed TiO 2 nanoparticles, the conductive MXene network and the improved electrochemical kinetics, the NC-TiO 2 /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 TiO 2 -based composites with enhanced electrochemical performance . • The NC-TiO 2 /MXene is synthesized by utilizing polyethyleneimine (PEI) and Ti 3 C 2 T x MXene as precursors. • The TiO 2 content in NC-TiO 2 /MXene is 76.1 wt% because of adequate oxidation reaction in the Ti 3 C 2 T x MXene. • The NC-TiO 2 /MXene electrode delivers excellent cycling ability and rate performance in SIBs.