Freestanding 1T-MnxMo1-xS2-ySey and MoFe2S4-zSez Ultrathin Nanosheet-Structured Electrodes for Highly Efficient Flexible Solid-State Asymmetric Supercapacitors

Fabrication of hierarchical nanosheet arrays of 1T phase of transition-metal dichalcogenides is indeed a critical task, but it holds immense potential for energy storage. A single-step strategy is employed for the fabrication of stable 1T-MnxMo1-xS2-ySey and MoFe2S4-zSez hierarchical nanosheet arrays on carbon cloth as positive and negative electrodes, respectively. The flexible asymmetric supercapacitor constructed with these two electrodes exhibits an excellent electrochemical performance (energy density of approximate to 69 & x202f;Wh kg(-1)& x202f;at a power density of 0.985 & x202f;kW & x202f;kg(-1)) with ultralong cyclic stability of approximate to 83.5% capacity retention, after 10 000 consecutive cycles. Co-doping of the metal and nonmetal boosts the charge storage ability of the transition-metal chalcogenides following enrichment in the metallic 1T phase, improvement in the surface area, and expansion in the interlayer spacing in tandem, which is the key focus of the present study. This study explicitly demonstrates the exponential enhancement of specific capacity of MoS2 following intercalation and doping of Mn and Se, and Fe2S3 following doping of Mo and Se could be an ideal direction for the fabrication of novel energy-storage materials with high-energy storage ability.