Seed-assisted synthesis of hierarchical α-MnO2/Nitride TiO2 taper nanorod arrays on carbon fiber paper with enhanced supercapacitor performance

A hierarchical porous alpha-MnO2 nanowire network and long nitrided TiO2 (N-TiO2) taper nanorod arrays are grown on seeded carbon fiber paper (SCFP) by a two-step hydrothermal synthesis. The alpha-MnO2/N-TiO2/SCFP electrode shows a high areal capacitance of 400.3 mF cm(-2) at 1.34 mA cm(-2), excellent cycling stability with no capacitance reduction after 5000 cycles, and good rate capability. The areal capacitance of alpha-MnO2/N-TiO2/SCFP is much larger than that of alpha-MnO2/N-TiO2 grown on carbon fiber paper without seeding (alpha-MnO2/N-TiO2/CFP). The enhanced performance can be attributed to the more open longer taper nanorod structure to achieve more favorable electrolyte ion access and provide larger specific surface allowing for improved and effective mass loading of active materials. The alpha-MnO2/N-TiO2/SCFP may provide a general method for increasing the areal capacitance of composite electrode by adjusting the structure of the nanostructured current collectors using a simple and effective seeded hydrothermal synthesis.