Bi2S3 nanosheet/ZnCo2O4 nanosphere arrays on Ni foam for high-performance battery-supercapacitor hybrid device

A Bi₂S₃/ZnCo₂O₄/Ni foam (NF) composite electrode is synthesized through a two-stage hydrothermal process to grow ZnCo₂O₄ nanospheres and Bi₂S₃ nanosheets in-situ on NF. The unique three-dimensional (3D) nano-array architecture electrode, which consists of ZnCo₂O₄ nanospheres and Bi₂S₃ nanosheets, exhibits an expanded electroactive surface area with abundant accessible active sites for electrochemical reactions. The synergistic effect of the two components and two morphologies of ZnCo₂O₄ and Bi₂S₃ leads to a satisfactory specific capacity (SC) (421.2 mA h/g at 1 A/g) for the Bi₂S₃/ZnCo₂O₄/NF. Additionally, the 3D nano-array architecture endows the Bi₂S₃/ZnCo₂O₄/NF remarkable cycling stability with capacity retention 91.64 % after 5000 cycles. The Bi₂S₃/ZnCo₂O₄/NF//AC (activated carbon)/CC (carbon cloth) battery-supercapacitor hybrid device (BSHD) exhibits an energy density of 101.2 W h/kg at a power density of 800 W/kg. It also demonstrates a remarkable cycling stability, retaining 80.13 % of its initial SC even after 1500 consecutive cycles. Evidently, the Bi₂S₃/ZnCo₂O₄/NF electrode holds significant potential for its implementation in BSHD applications, opening up new possibilities in the energy storage and conversion.