Sulfur incorporation modulated absorption kinetics and electron transfer behavior for nitrogen rich porous carbon nanotubes endow superior aqueous zinc ion storage capability

Aqueous zinc ion hybrid capacitors (ZHCs) are considered as one of the most promising candidates for energy storage devices due to their low cost, high safety and excellent lifespan. However, cathode candidates with satisfactory energy density and cycling stability are still a great challenge. Herein, we present that sulfur incorporation into nitrogen rich porous carbon nanotubes (SN-PCNTs) can effectively modulate the absorption kinetics and the electron transfer behavior to enhance the aqueous Zn2+ storage capability. Specifically, SN-PCNT based ZHCs deliver a high energy density of 95.9 Wh kg(-1) at a power density 125 W kg(-1) and a superb power density of 19 170 W kg(-1) with a decent energy density of 21.3 Wh kg(-1), along with an ultralong lifespan up to 25 000 cycles with a capacity retention rate of 93.5%. Density functional theory simulations reveal that sulfur incorporation can significantly improve the absorption kinetics of Zn2+ and modulate the electron transfer behavior. This work provides a unique route to effectively improve the Zn2+ storage performance of carbon materials through sulfur incorporation, which is expected to push forward the advancement of aqueous energy storage devices.

Automated summary

This study demonstrates that sulfur incorporation into nitrogen-rich porous carbon nanotubes can effectively enhance the storage capability of aqueous zinc ion hybrid capacitors (ZHCs), leading to high energy density, superb power density, and long lifespan.