Hollow CoS2 anchored on hierarchically porous carbon derived from Pien Tze Huang for high-performance supercapacitors

The development of electrode materials with a high specific capacitance, power density, and long-term stability is essential and remains a challenge for developing supercapacitors. Cobalt sulfides (CoS2) are considered one of the most promising and widely studied electrode materials for supercapacitors. Herein, CoS2 and hierarchical porous carbon derived from Pien Tze Huang waste are assembled into a cobalt sulfide/carbon (CoS2/PZH) matrix composite using a one-step hydrothermal method to resolve the challenges of supercapacitors. The resulting CoS2/PZH composite material exhibits a hierarchical porous structure with hollow CoS2 embedded in a PZH framework. The uniform dispersion of the hierarchical porous structure CoS2/PZH is achieved due to the PZH framework, while the uniform decoration of the porous PZH with the hollow CoS2 prevents the PZH from stacking easily. Moreover, the excellent synergistic effect of the hierarchical porous and hollow structure of CoS2/PZH can shorten the electron/ion diffusion channels, expose additional active sites, and provide stable structures for subsequent reactions. As a result, the CoS2/PZH composite material displays a high initial specific capacity of 447.5 F g-1 at 0.5 A g-1, a high energy density of 22.38 W h kg-1, and long-term cycling stability (a retention rate of 92.3% over 10 000 cycles at 5 A g-1).