Seed‐Assisted Synthesis of Hierarchical α‐MnO2/Nitride TiO2 Taper Nanorod Arrays on Carbon Fiber Paper with Enhanced Supercapacitor Performance

A hierarchical porous α‐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 α‐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 α‐MnO2/N‐TiO2/SCFP is much larger than that of α‐MnO2/N‐TiO2 grown on carbon fiber paper without seeding (α‐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 α‐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. Nitride TiO2 taper nanorod arrays are successfully prepared on carbon fiber paper by a novel seeded hydrothermal synthesis and thermal nitridation (nitrided TiO2 [N‐TiO2]/seeded carbon fiber paper [SCFP]), and then used as a highly conductive collector for a subsequent hydrothermal synthesis of α‐MnO2 (α‐MnO2/N‐TiO2/SCFP). The areal capacitance of α‐MnO2/N‐TiO2/SCFP is much larger than that of α‐MnO2/N‐TiO2 grown on carbon fiber paper without seeding (α‐MnO2/N‐TiO2/CFP).