Asymmetric supercapacitors assembled by hollow N, s co-doped carbon spheres decorated FeOOH and Co3S4 nanoparticles

Exploiting advanced anode and cathode materials with distinctive architectures and multi-component participation is of great significance to boosting the energy density of asymmetric supercapacitors. Herein, ultra-fine FeOOH nanoparticles are in situ grown on the hollow N, S co-doped carbon (HNSC) spheres using a facile solvothermal strategy and subsequent calcination process. Benefiting from the attractive hollow architecture and the synergistic effect between FeOOH and HNSC, the FeOOH/HNSC composite as anode for supercapacitors delivers an optimal capacity of 588.2 C g(-1) (1 A g(-1)) and remains 88.3 % of its initial value after 10,000 cycles at 15 A g(-1) in 6 M KOH. Furthermore, the HNSC-supported Co3S4 nanoparticles are also prepared through a one-step solvothermal strategy. The obtained Co3S4/HNSC composite as cathode achieves a capacity of 420 C g(-1) (1 A g(-1)) and maintains a high retention of 95.3 % after 10,000 cycles at 15 A g(-1). The constructed asymmetric supercapacitor using FeOOH/HNSC and Co3S4/HNSC as anode and cathode appears to possess a superior energy density of 82.3 Wh kg(-1) at 821.6 W kg(-1) with retention of 84.9 % after 10,000 cycles at 10 A g(-1). These attainments demonstrate that constructing multi-component electrode materials with unique structures is an effective method to optimize the electrochemical characteristics of asymmetric supercapacitors.