Titanium dioxide nanobelts modified with manganese dioxide nanoflakes for high-performance supercapacitor applications

One-dimensional TiO₂ nanobelts (TiO₂ NBs) loaded with MnO₂ nanoflakes (MnO₂ NFs) were fabricated by coating of pre-synthesized H₂Ti₃O₇ NBs with carbon layer followed by annealing in Ar atmosphere and hydrothermal treatment with KMnO₄ solution. Then, disclosed by SEM and TEM inspections, interconnected MnO₂ NFs were uniformly deposited on the surface of TiO₂ NBs, forming the final products of TiO₂@MnO₂ nanobelts (TiO₂@MnO₂ NBs) with unique core–shell nanostructures. The supercapacitive properties of the TiO₂@MnO₂ NBs were studied using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. Compared with bare MnO₂ NFs, the TiO₂@MnO₂ NBs exhibit enhanced rate performance and excellent cycle stability because of the synergistic effect of the two metal oxides. For instance, TiO₂@MnO₂ NB electrode released a specific capacitance of 113.3 F g⁻¹ in 1 M Na₂SO₄ solution at a current density of 0.1 A g⁻¹. After performing 10,000 charge–discharge cycles, such composite electrode retained 99.6% of the initial specific capacitance. We also constructed a TiO₂@MnO₂ NB//TiO₂@MnO₂ NB symmetrical supercapacitor device, which offered an energy density of 4.04 Wh kg⁻¹ with long-term cycle stability. The satisfactory electrochemical behaviors would make TiO₂@MnO₂ NBs a reliable candidate material for the building of high-stability energy storage devices.