A Hollow-Shaped ZIF-8-N-Doped Porous Carbon Fiber for High-Performance Zn-Ion Hybrid Supercapacitors

Abstract

The advantages of low cost, high theoretical capacity, and dependable safety of aqueous zinc ion hybrid supercapacitors (ZHSCs) enable their promising use in flexible and wearable energy storage devices. However, achieving extended cycling stability in ZHSCs is still challenged by the limited availability of carbon cathode materials that can effectively pair with zinc anode materials. Here, we report a method for synthesising heteroatom-doped carbon nanofibers using electrostatic spinning and metal-organic frameworks (specifically ZIF-8). Assembled Zn//ZPCNF-1.5 ZHSCs exhibited 193 mA h g−1 specific capacity at 1 A g−1 and 162.6 Wh kg−1 energy density at 841.2 kW kg−1. Additionally, the device showed an ultra-long cycle life, maintaining 98% capacity after 20,000 cycles. Experimental analysis revealed an increase in the number of pores and active sites after adding ZIF-8 to the precursor. Furthermore, N doping effectively enhanced Zn2+ ions chemical adsorption and improved Zn-ion storage performance. This work provides a feasible design strategy to enhance ZHSC energy storage capability for practical applications.