Multilayer Core–Sheath Wires with Radially Aligned N-Doped Carbon Nanohole Arrays for Boosting Energy Storage in Zinc-Ion Hybrid Supercapacitors

Aqueous zinc-ion hybrid supercapacitors (ZHSCs) with the characteristics of low cost, long cycle stability, and good safety have been regarded as potential candidates for wearable energy storage applications. Herein, we reasonably designed a unique binder-free nitrogen-doped (N-doped) porous carbon@TiO₂@Ti multilayer core-sheath wire (N-CTNT), which has vertical N-doped carbon nanoholes radially aligned on the wire surface. The unique structure and nitrogen dopants of N-CTNTs have facilitated zinc deposition on N-CTNT to form a hierarchical and robust zinc-carbon composite (Zn@N-CTNTs). A wire-shaped ZHSC was constructed with N-CTNTs and Zn@N-CTNTs as cathode and anode electrodes, respectively. The as-prepared ZHSC has an outstanding specific capacitance of 488 mF cm^-2 at 1 mA cm^-2. This hybrid supercapacitor also exhibits an excellent energy density of 211 μW h cm^-2, good rate performance, and long cycle stability with a capacity retention rate of 90.4% after 16,000 cycles.