CoS2 nanosheets on carbon cloth for flexible all-solid-state supercapacitors

Abstract

Although all-solid-state hybrid supercapacitors (HSCs) based on cobalt sulfides are revealed to procure high density of redox species, their rate performance and power are severely restricted by adverse bulk structure of the electrode materials. Here, through regulating the sulfuric agents with mutative activities to rationally vulcanize cobalt-MOF, we fabricate hierarchical CoS2 nanosheet arrays directly coated on the conductive carbon cloth (CC@CoS2). These nanosheets are featured with unique macropore-mesopore-micropore porous architecture providing multi-level channels for rapid diffusion of ions, as well as abundant periphery sites from the refined nanoparticles in favor of the pseudocapacitive reaction. Electrochemical studies indicate that the structural superiorities of the CC@CoS2 effectually accelerate ions diffusion and retard the kinetic hysteresis. Consequently, an all-solid-state HSC with the CC@CoS2 and nitrogen-doped carbon nanosheet arrays grown vertically on carbon cloth as cathode and anode, respectively, achieves synchronous high energy density of 3.16 mWh·cm−3 and power density up to 1.61 W·cm−3, as well as robust cyclic stability (86.2% retention after 16,000 cycles). Besides, the electrochemical behavior of the HSC also shows good reliability under multiple mechanical deformation conditions and thermal circumstances. This work demonstrates a universal, effective strategy to produce advanced textile electrodes for flexible all-solid-state energy storage applications.