Insight into the synergistic effect of 2D/2D layered metal selenides wrapped nickel boride nanoparticles based ternary heterostructure for constructing asymmetric supercapacitors with excellent energy density

Tuning the structural and electronic properties of layered metal selenides is a highly feasible approach for developing high-performance asymmetric supercapacitors (ASCs). In this work, a ternary heterostructure of yttrium diselenide/molybdenum diselenide (YSe2/MoSe2) with amorphous nickel boride nanoparticles (NixB NPs) was prepared by a simple hydrothermal method followed by a liquid phase route. Interestingly, this ternary heterostructure consists of multiple layers of YSe2/MoSe2 nanosheets uniformly wrapped by NixB NPs over the entire surface. The characterization results by X-ray diffraction, Raman, and X-ray photoelectron spectroscopy showed that the strong synergism between YSe2/MoSe2 and NixB NPs indicates an obvious electron transfer from NixB to the YSe2/MoSe2 hybrid, which contributes to the enhancement of the electrical conductivity of the electrode. Due to its exclusive heterostructure network, the single YSe2/MoSe2/NixB electrode achieved a specific capacitance of 893.3 F/g at 1 A/g and a capacity retention of 128.17% over 5000 cycles. In addition, the asymmetric YSe2/MoSe2/NixB||rGO device with a working potential of 1.6 V showed an impressive energy density of 39.5 Wh kg(-1) with a power density of 800 W kg(-1) and excellent cycling stability with 85.60% capacity retention after 5000 cycles in aqueous electrolyte. This result of the designed ASC device encourages the development of a new platform for the design of electrode materials based on metal selenides and metal borides.