Porous nanoframes of sulfurized NiAl layered double hydroxides and ternary bismuth cerium sulfide for supercapacitor electrodes

Manipulating the structure of electroactive materials with hierarchical frameworks can boost the electrochemical properties. The soaring fidelity of mixed nanostructured materials in electrochemistry verifies their candidature as appropriate electrodes for sustainable energy storage and conversion devices. Herein, we present facile and economical techniques to develop three-dimensional (3D) hierarchical nanoframes-like sulfurized nickel aluminum (sulfurized NiAl) as a positive electrode material and ternary bismuth cerium sulfide (Bi-Ce-S) as the negative electrode material for constructing an aqueous asymmetric supercapacitor system. These hierarchical architectures with well-developed pores and hollow spaces can capitalize the surface-to-volume ratio and maximize the contact area between the active material and electrolyte, therefore immensely reduce the ion penetration distances and promote the electron transport rates. Tuning the conductivity of electrode materials affords rich contact sites and integrates the features of all components, thus resulting in better electrochemical enhancements. As expected, sulfurized NiAl nanosheet arrays with unique porous architectures exhibit a good electrochemical performance with commendable specific capacitance of 1230.6 F g(-1)- at 1 A g(-1) current density and stable rate capability (69.8% up to 20 A g(-1)). In addition, the obtained Bi-Ce-S hybrid provides a high specific capacitance (411.7 F g(-1) at 1 A g(-1)) with 92.2% capacitance retention even after 4000 cycles. An asymmetric supercapacitor (ASC) device is established with the designed composites, which realizes a high energy density of 38.5 Wh kg(-1) at a power density of 750 W kg(-1) and reveals an enhanced cycle stability (80.6% retention after 8000 GCD times).