Improvements in the Magnesium Ion Transport Properties of Graphene/CNT‐Wrapped TiO₂‐B Nanoflowers by Nickel Doping

Abstract Magnesium‐ion batteries are widely studied for its environmentally friendly, low‐cost, and high volumetric energy density. In this work, the solvothermal method is used to prepare titanium dioxide bronze (TiO₂‐B) nanoflowers with different nickel (Ni) doping concentrations for use in magnesium ion batteries as cathode materials. As Ni doping enhances the electrical conductivity of TiO₂‐B and promotes magnesium ion diffusion, the band gap of TiO₂‐B host material can be significantly reduced, and as Ni content increases, diffusion contributes more to capacity. According to the electrochemical test, TiO₂‐B exhibits excellent electrochemical performance when the Ni element doping content is 2 at% and it is coated with reduced graphene oxide@carbon nanotube (RGO@CNT). At a current density of 100 mA g⁻¹, NT‐2/RGO@CNT discharge specific capacity is as high as 167.5 mAh g⁻¹, which is 2.36 times of the specific discharge capacity of pure TiO₂‐B. It is a very valuable research material for magnesium ion battery cathode materials.