N, P, and S co-doped 3D porous carbon-architectured cathode for high-performance Zn-ion hybrid capacitors

Abstract

Zinc (Zn) ion hybrid capacitors (ZIHCs) are promising energy storage devices with the integrated merits of high-capacity Zn-ion batteries and high-power supercapacitors. Their practical application yet remains a challenge due to the relatively low energy density and poor longevity. Herein, a hierarchical porous carbon sphere (HPCS) co-doped with N, P and S is developed, which is featured with a three-dimensional (3D) porous frame structure to deliver a short mass transfer pathway, fast kinetics and enhanced conductivity. The ZIHCs with HPCS-900 as the cathode material enables a large capacity of 104.7 mA h g⁻¹ and excellent energy/power density of 90.17 W h kg⁻¹/81.2 W kg⁻¹ within the voltage window of 0.1–1.7 V. The HPCS-900-based ZIHCs affords a high stability up to 30 000 cycles with a high capacity retention of 95.24%. The HPCS-900 coupled soft-pack ZIHC device exhibits high capacity, high-rate capability and high stability, indicating the great potential of ZIHCs in practical applications.